• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.397-398
• /
• 2009

최근 알칼리 활성 콘크리트에 관한 연구가 활발히 진행되고 있는 실정이다. 본 연구에서는 여러 종류의 알칼리 활성화제가 플라이애시 기반 시멘트 ZERO 모르타르에 미치는 영향을 검토하였다.

• 대한환경공학회지
• /
• 제28권6호
• /
• pp.661-666
• /
• 2006

칼슘함량이 낮은 F급 플라이 애쉬와 알칼리 활성화 용액으로 구성된 페이스트의 압축강도 특성에 대한 연구를 수행하였다. 수산화나트륨과 물유리 그리고 물을 혼합하여 제조한 이들 활성화 용액은 매우 높은 $OH^-$ 농도를 가지고 있다. 알칼리 활성화 용액의 조성과 온도는 플라이 애쉬-시멘트 페이스트의 압축강도 발현에 대한 현저한 영향 인자임을 보여주었다. 50 MPa 이상의 압축강도는 플라이 애쉬를 각각 $60^{\circ}C$에서 48시간과 $85^{\circ}C$에서 24시간 양생하여 얻었다. 본 연구결과, F급 플라이 애쉬/NaOH/물유리의 무게 비율 25:8:2와 활성화 용액/플라이 애쉬의 무게 비율 0.6/1.0은 높은 강도를 가진 페이스트를 위한 적정 혼합비율로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제8권2호
• /
• pp.162-165
• /
• 2003

In order to study the secretion of the human urokinase-type plasminogen activator, u-PA, from the yeast yarrowia lipolytica, three kinds of integrative expression vector were constructed. These vectors differed only in their secretion control legions, pre-, pre-dip-(dipeptide Stretch) or pre-dip-pro sequences of the alkaline extracellular protease, which were joined inflame to the human u-PA cDNA. The recombinant Y. lipolytica Strains, transformed with the expression vectors, secreted the hyperglycosylated u-PA. A fibrin plate assay of the culture supernatants showed that the hyperglycosylated u-PA proteins could catalyze fibrinolysis, and that the pre-dip sequence was the most efficient secretory signal for the secretion of the u-PA from Y. lipolyica. This result suggests that Y. lipolytica can be developed as a potential host for the production of recombinant human u-PA.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 추계 학술논문 발표대회
• /
• pp.217-218
• /
• 2011

The advantages of blast-furnace slag concrete may include lower hydration heating velocity, restraint on concrete temperature increase, long-age strength improvement due to latent hydraulic reaction, improved water tightness, and repulsion to chemical erosion. These advantages contribute to the high quality of the blast-furnace slag concrete. However, the blast-furnace slag concrete has its limitations as well. These disadvantages may include retarded setting and elongated retention of mold due to the weak strength of early-age. Nevertheless, much research is currently under way to improve the aforementioned issues. To improve activity of blast furnace slag powder, alkaline irritants has been used. In this study, we analyze effect on activity fineness and rate of substitution of Alkali Activator toward activity.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.789-792
• /
• 2006

The purpose of this study is to investigation the fundamental properties of alkali activated slag of type and concentration of alkali activator. In this paper sodium silicate, sodium carbonate and sodium hydroxide were used as alkaline activator and their concentration were 1, 3, 5 and 7 $Na_2O$ weight percent. The physical properties of alkali activated blast furnace slag cement mortar (AAS) were investigated by flow test and compressive strength. And the hydration properties of AAS characterized by X-ray diffraction and scanning electron microscope. Result show that Alkali activated slag mortar strengths were continuously increased with adding amount and ages. C-S-H were formed to be the main products up to 28days of hydration.

• 대한치과교정학회지
• /
• 제30권6호
• /
• pp.713-721
• /
• 2000

골세포는 골대사에 영향을 미치는 다양한 성장인자와 싸이토카인을 생성하여 골 기질로 유리시킨다. 이 연구는 쥐의 장골 세포 배양 모델에서 recombinant human IL-$1\beta$가 $PGE_2$ 합성과 plasminogen activator의 활성 조절을 통한 골 흡수 유도 기전의 일단을 구명하고, 이와 동시에 TGF-$\beta$에 의한 골흡수 억제 기전을 해명하는데 그 목적이 있다. 쥐의 장골 세포를 배양하여 통법의 골모세포 phenotype을 발현하는 세포를 분리하고 세포 배양능, alkaline phosphatase assay, PG assay, 골흡수능 측정들을 시행하여 다음의 결과를 얻었다. 1. IL-$1\beta$는 쥐의 골모세포의 증식, $PGE_2$ 생성 및 palsmonogen activator의 활성을 촉진하였다. 2. IL-$1\beta$는 쥐의 골모세포에서의 alkaline phosphatase 활성을 감소시켰다. 3. rhIL-$1\beta$는 골 흡수를 촉진시켰다. 4. TGF-$\beta$는 쥐의 장골 세포에서 골의 흡수를 억제하였으며, Vitamin $D_3$에 의하여 유도된 골 흡수를 억제하였다. 이상의 연구 결과는 IL-$1\beta$에 의한 골 파괴의 병인과 관련하여 골 세포 대사의 병리학적 조절에 있어서의 IL-$1\beta$의 역할을 지지하며, 이와 동시에 골 흡수 억제에 있어서의 TGF-$\beta$의 역할을 확인시켜주는 것으로 생각된다.

• Advances in concrete construction
• /
• 제2권1호
• /
• pp.29-37
• /
• 2014

Increasing emphasis on energy conservation and environmental protection has led to the investigation of the alternatives to customary building materials. Some of the significant goals behind understaking such investigations are to reduce the greenhouse gasemissions and minimize the energy required formaterial production.The usage of concrete around the world is second only to water. Ordinary Portland Cement (OPC) is conventionally used as the primary binder to produce concrete. The cement production is a significant industrial activity in terms of its volume and contribution to greenhouse gas emission. Globally, the production of cement contributes at least 5 to 7 % of $CO_2$. Another major problem of the environment is to dispose off the fly ash, a hazardous waste material, which is produced by thermal power plant by combustion of coal in power generation processes. The geopolymer concrete aims at utilizing the maximum amount of fly ash and reduce $CO_2$ emission in atmosphere by avoiding use of cement to making concrete. This paper reports an experimental work conducted to investigate the effect of curing conditions on the compressive strength of geopolymer concrete prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2020년도 가을 학술논문 발표대회
• /
• pp.77-78
• /
• 2020

An alkaline activator was synthesized by dissolving waste glass powder (WGP) in NaOH-4M solution to explore its effects on the Class-C fly ash (FA) and ground granulated blast furnace slag (GGBS) based alkali-activated material (AAM). The compressive strength and porosity were measured, and (SEM-EDX) were used to study the hydration mechanism and microstructure. Results indicated that the composition of alkali solutions was significant in enhancing the properties of the obtained AAM. As the amount of dissolved WGP increased in alkaline solution, the silicon concentration increased, causing the accelerated reactivity of FA/GGBS to develop Ca-based hydrate gel as the main reaction product in the system, thereby increasing the strength. Further increase in WGP dissolution led to strength loss, which were believed to be due to the excessive water demand of FA/GGBS composites to achieve optimum mixing consistency. Increasing the GGBS proportion in a composite also appeared to improve the strength which contributed to develop C-S-H-type hydration.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.136-137
• /
• 2021

The soda lime waste glass powder was dissolved in NaOH-4M solution to synthesize an alkaline activator, which was used to activate Class-C fly ash (FA). Compressive and flexural strength tests were conducted to determine the mechanical properties. Archimedes' principle was applied to measure the porosity of samples, (SEM-EDX) and XRD was used to study the microstructure and phase changes of samples. Through Inductive Coupled Plazma technique, the solution was found to increase the concentration of Si as the amount of dissolved glass powder was increased. Owing to the increased concentration of Si in an alkaline solution, the reactivity of FA was accelerated resulting in an increased strength and reduced porosity. Additionally, the dissolution of FA was improved as well as the formation of amorphous phases in the matrix was also enhances with the concentration of increased Si in an alkaline solution.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.555-559
• /
• 2001

A by-product, waste sludge water produced from ready mixed concrete(remicon) factories may affect our environmental contamination if it is discharged without proper waste disposal. In Korea, all waste sludge water has been recycled in the way of mixing water of remicon, but the quality of the concrete then produced can be deteriorated, so it might cause slump loss or irregular compressive strength. In this study, waste sludge water is divided into two parts, remicon sludge and residual water in order to make it's property more stable. Then, the remicon sludge and high-alkaline residual water were used as admixture and alkali activator respectively. In this paper we research about quality of with remicon sludge and residual water and performed the fundamental properties of cement matrix mixed with remicon sludge and residual water.