• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.84-88
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• 1995

The results of an experimental study on manufacture and mechanical properties of concrete utilizing crushed sand and fly ash for construction materials are presented in theis paper. As the results show, the workability, compressive strength and freezing-thaw resistance were improved by proper contents of fly ash, replaced crushed sand, and air entraining agent. And the drying shinkage was decreased by proper contents of those. Also, the suitable weight contents of replacing ratio of crushed sand and weight ratio fly ash in concrete using crushed sand were in range of 30% and 15% respectively.

• Journal of Microbiology
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• v.34 no.4
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• pp.384-386
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• 1996

Application of polyacrylamide gel (PAG) instead of agar to solid cultures of Streptomyces spp. was studied. The improved media were prepared by 1) gelling 20 ml of 5% acrylamide in a glass petri dish at room temperature, 2) washing by running water for more than 8 hr to remove residual reaction reagents, 3) drying at 5$0^{\circ}C$ for 12 hr to make a gel film, 4) autoclaving at 121$^{\circ}C$ for 15 min, and 5) swelling gel for about 4 hr by adding sterile liquid medium. In PAG media there were no differences from the observation of morphological characteristics showing during the cellular differentiation on agar media, whereas the ability to utilize carbohydrates differed somewhat from agar media. Agar media thus were little favorable for biochemical tests which the growth was determined depending on the formation of colony, but washed PAG was superior to serve as a solidifying agent.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.164-165
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• 2021

To prepare the good-adherent and weather-resistant acrylic resin coatings, acrylic resin was prepared by a radical polymerization. Glass transition temperature(Tg) of the acrylic copolymer was fixed at 30℃ and the contents of tertiary amine monomer(DMAEMA) was varied to be 5, 10, 15, 20 wt% respectively. γ-Glycidoxypropyltrimethoxysilane(GPTMS) containing epoxy group was used for curing agents and di-n-butyltindilaurate(DBTDL) was used for drying accelerator. The equivalent ratio of amine to epoxy was 1:1. The prepared coatings exhibited excellent adhesion to various substrates, and various physical properties of the coatings were satisfactory. The gloss retention and color difference were improved at low tertiary amine concentration. The coatings containing 10wt% tertiary amine concentration have especially good weather resistant properties.

• Journal of the Korean Home Economics Association
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• v.46 no.6
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• pp.13-19
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• 2008

In this paper, the dyeing ability of the volcanic ash dyeing on cotton knitted fabrics were investigated. Acrylic copolymer was used to improve the depth of fabric color in the dyeing process. K/S values of dyed fabrics were measured to examine the dyeing properties. Two different classes of dyeing process were tested; (1) volcanic ash dyeing after pretreatment and (2) simultaneous co-treatment with volcanic ash and acrylic copolymer. In the first process, the effects of parameters such as the concentration of volcanic ash, concentration of Na2S04, dyeing time, dyeing temperature and pH of dyebath were noted. In the second process, the effects of parameters such as concentration of acrylic copolymer, dyeing time and temperature, and drying temperature were noted. Experimental results showed that the co-treatment of acrylic copolymer improved the dyeing properties of cotton knitted fabrics with volcanic ash. For the first dyeing experiment, concentration of dispersing agent was 0.1%, concentration of volcanic ash was 4%, treatment time was 20minutes, concentration of $Na_2SO_4$ was 2%, treatment temperature was $60^{\circ}C$ and treatment pH of dyebath was neutral. In the second dyeing experiment, concentration of acrylic copolymer was 2%, treatment temperature was $80^{\circ}C$, treatment time was 40 minutes, and treatment drying temperature was $150^{\circ}C$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.299-305
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• 2012

The objective of this paper is to obtain the basic data in order to develop an eco-friendly concrete through evaluation on the properties of polymer cement mortar and concrete using PVAc (Polyvinyl Acetate), as a kind of water-soluble polymer. For this purpose, the physical properties of cement mortar and concrete which does not contain the PVAc as the control batch were compared and analyzed with those using the PVAc. And then, the replacement amount of the PVAc was 3%, 6%, 9% and 12% by binder, respectively. And also, the properties of concrete using the PVAc were evaluated, by adding an antifoaming agent in order to control the air contents increasing with an increase of amount of polymer usage. As a result, in the case of polymer cement mortar using the PVAc, it presented that the compressive strength reduced, while the performance of flexural strength and drying shrinkage increased. When the replacement of the PVAc was 6% within concrete, the compressive, tensile, flexural strength and elastic modulus were increased.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.303-311
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• 2016

Objectives: Allergic asthma generally presents with symptoms of wheezing, coughing, breathlessness, and airway inflammation. Seonpyejeongcheon-tang (SJT) consists of 12 herbs. It originated from Jeong-cheon-tang (JT), also known as Ding-chuan-tang, composed of 7 herbs, in She-sheng-zhong-miao-fang. This study aimed to evaluate the effects of local delivery of SJT via inhalable microparticles in an asthma mouse model. Methods: Microparticles containing SJT were produced by spray-drying with leucine as an excipient. SJT microparticles were evaluated with respect to their aerodynamic properties, in vitro cytotoxicity, in vivo toxicity, and therapeutic effects on ovalbumin (OVA)-induced asthma in comparison with orally-administered SJT. Results: SJT microparticles provided desirable aerodynamic properties (fine particle fraction of $48.9%{\pm}6.4%$ and mass median aerodynamic diameter of $3.7{\pm}0.3{\mu}m$). SJT microparticles did not show any cytotoxicity against RAW 264.7 macrophages at concentrations of 0.01 - 3 mg/mL. Inhaled SJT microparticles decreased the levels of IL-4, IL-5, IL-13, IL-17A, eotaxin and OVA-IgE in bronchoalveolar lavage fluid (BALF) in mice with OVA-induced asthma. These effects were verified by histological evaluation of the levels of infiltration of inflammatory cells and collagen, destructions of alveoli and bronchioles, and hyperplasia of goblet cells in lung tissues. The effects of SJT microparticles in the asthma model were equivalent to those of orally-administered SJT extract. Conclusion: This study suggests that SJT is a promising agent for inhalation therapy for patients with asthma.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.450-457
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• 2017

This study is to develop high quality floor mortar which can be applied in construction sites using EXFG(Expansive admixdure Flue Gas desulfurization gypsum). First, as the substitution rate of ALS(Aluminum Slag) increased, the flow is increased proportionally. EXFG showed a tendency to decrease with increasing substitution rate. Also, in the case of the setting time of 5% of ALS replacement rate, the setting time of Plain compared to EXFG was decreased by 5~20%. The compressive strength increased with the ALS replacement ratio at 0%, 5% and the EXFG replacement ratio at 1%. The strength was increased when the ALS replacement ratio was more than 10%. In the case of ALS replacement rate of 0% and 5%, drying shrinkage compared to plain was decreased by about 10~25% regardless of EXFG replacement rate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.34-40
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• 2014

High-performance fiber-reinforced cement composite (HPFRCC) shows very high autogenous shrinkage, because it contains a low water-to-binder ratio (W/B) of 0.2 and high fineness admixture without coarse aggregate. Thus, it needs a method to decrease the cracking potential. Accordingly, in this study, to effectively reduce the shrinkage of HPFRCC, a total of five different ratios of SRA (1% and 2%), EA (5% and 7.5%), and a combination of SRA and EA (1% and 7.5%) were considered. According to the test results of ring-test, a combination of SRA and EA (1% and 7.5%) showed best performance regarding restrained shrinkage behavior without significant deterioration of compressive and tensile strengths. This was also verified by performing modified drying shrinkage crack test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.17-20
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• 2005

This study investigates mock-up test of the concrete containing crushed sands with improved quality and following could be draws as conclusions. The slump satisfies the target value. The air content reaches the goal, however, it decreases by the occurrence of loss with elagse of age. In normal strength region, the setting time of CS24 member is shorter than that of SS24 member. In high strength region, the setting time of SS50 member is make only slower than that of CS5O because of the use of retarding AE agent. The compressive strength of the concrete using crushed sands is little higher than the concrete using washed sea sands, and the compressive strength of core sample increases at lower part. Drying shrinkage of the concrete using crushed sands is larger than that using washed sea sands. At water caring condition, both the concrete using crushed sands and using washed sands expand at first, exhibit to be swelled and with elagse of age, they remain relatirely constant. Also, the drying shrinkage occurred greatly when the width and thickness of a member are small because it is easy to evaporate the inner part vapor in the small width and thickness of a member. there can be little different according to the location of a contact gauge, however it is similar to the change of specimen's length change. The concrete using crushed sands, of which grading, grain shape and fine particle is improved, are comparable to the quality of the concrete using washed sea sand.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.17-25
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• 2018

Purpose: When casting of ceramics, proper amount of deflocculant was added for disperse the particles in slip. In this study, examined the optimum amount of APMA(ammonium polymethaacrylate) water as deflocculant for casting the zirconia. Methods: The 100 g of zirconia powder were ball milled with 300 g zirconia ball, 90 g of distilled water, and APMA water in polyethylene pot for 24 hours. The amount of APMA water were added as deflocculant from 0.5 to 0.9 g at an intervals of 0.1 g. The viscosity of slip with no deflocculant showed 1362c.p. and the minimum viscosity with 580c.p. obtained when the slip contained 0.7% of deflocculant. Bar type specimens were casted with plaster mold and biscuit fired at $1100^{\circ}C$ for 1 hours. Biscuit fired specimens were finished with $60mm(L){\times}14mm(W){\times}10mm(H) bar$. Finished specimens were 2nd fired at $1500^{\circ}C$ for 1 hour. Results: Regardless the addition of deflocculant, all 2nd fired specimens showed 0% of apparent porosity and water absorption. The specimens with no deflocculant showed 24% of drying shrinkage and 27.4% firing shrinkage. On the other hand, The specimens with deflocculant showed 17.4% of drying shrinkage and 17.6% firing shrinkage regardless the amount of deflocculant. The maximum bulk density with $6.09g/cm^3$ obtained when the specimens casted with 0.7~0.9% of deflocculant contained slips. Bend strength of specimen with no deflocculant showed 680 MPa and the maximum bend strength with 814 MPa obtained when the specimen casted with 0.7% of diflocculant contained slip. Conclusion : It was found that the particle shape of the powder according to the dispersing agent is added, the particle size, sintering temperature and affect the particle size distribution, sintering time, sintering atmosphere, such a great influence on the sintering.