• 한국압력기기공학회 논문집
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• 제20권1호
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• pp.49-55
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• 2024

Stainless 630 (or 17-4PH) is a precipitation-hardening martensitic stainless steel that has excellent mechanical properties and corrosion resistance. These characteristics make the STS630 to be used as a consisting material for various components such as spider, pin, spring, and spring retainer, of the control rod drive mechanism (CRDM) in pressurized water reactors (PWRs). In general, it is well known that the oxide layer of stainless steel consists of a duplex layer, a compact inner layer of FeCr₂O₄ spinel, and a coarse-grained outer layer of Fe₃O₄ spinel in PWR primary coolant condition. However, the characteristics of the oxide layer can be sensitively influenced by various water chemistry conditions such as temperature, dissolved oxygen, dissolved hydrogen, pH, pH adjuster type, and exposure time. In this work, we investigate the corrosion properties of the STS630 as a function of coolant temperature in an NH3 alkaline solution for its boron-free application in a small modular reactor, to confirm the feasibility for usage as a boron-free SMR structural material. As a result, oxide layer of corroded STS630 is consist of double-layer oxides consisting of a Cr-rich dense inner oxide and a Fe-rich polyhedral outer particles like as that in commercial PWR primary coolant. The corrosion rate of STS630 increases with increase in test time and temperature and the corrosion rate-time model equation was developed based on experimental data. Overall, it is expected that the results in this study provides useful data for the corrosion behavior of STS630 in alkaline environments, contributing to the development of selecting suitable materials for SMRs.

• Asian-Australasian Journal of Animal Sciences
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• 제1권4호
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• pp.195-199
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• 1988

Two experiments were conducted to evaluate the nutritive value of a diet containing 20% alkaline hydrogen peroxide(AHP) treated aspen sawdust for ruminants. In experiment 1, sheep fed treated aspen(treated) had higher (p < 0.05) average daily gain and improved feed/gain ratio compared to animals fed untreated aspen (untreated), Apparent NDF and ADF digestibilities of treated aspen were higher (p < 0.05) than for untreated material. A similar trend was observed for DM, organic matter and cellulose digestibilities coefficients. In experiment 2, the soluble and degradable DM and crude protein (CP) fractions tended to increase with AHP treatment. Treatment also increased (p<0.05) the degradation rate of the degradable fraction. Results of these experiment indicate that AHP treatment results in a substantial improvement in the extent of utilization of aspen sawdust by ruminants.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.545-545
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• 2008

Poly-Si is an essential material for floating gate in NAND Flash memory. To fabricate this material within region of floating gate, chemical mechanical polishing (CMP) is commonly used process for manufacturing NAND flash memory. We use colloidal silica abrasive with alkaline agent, polymeric additive and organic surfactant to obtain high Poly-Si to SiO2 film selectivity and reduce surface defect in Poly-Si CMP. We already studied about the effects of alkaline agent and polymeric additive. But the effect of organic surfactant in Poly-Si CMP is not clearly defined. So we will examine the function of organic surfactant in Poly-Si CMP with concentration separation test. We expect that surface roughness will be improved with the addition of organic surfactant as the case of wafering CMP. Poly-Si wafer are deposited by low pressure chemical vapor deposition (LPCVD) and oxide film are prepared by the method of plasma-enhanced tetra ethyl ortho silicate (PETEOS). The polishing test will be performed by a Strasbaugh 6EC polisher with an IC1000/Suba IV stacked pad and the pad will be conditioned by ex situ diamond disk. And the thickness difference of wafer between before and after polishing test will be measured by Ellipsometer and Nanospec. The roughness of Poly-Si film will be analyzed by atomic force microscope.

• International Journal of Industrial Entomology and Biomaterials
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• 제33권2호
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• pp.78-84
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• 2016

The antioxidant activity of silkworm powder treated by proteolytic enzyme was investigated. Total protein content of silkworm power was assayed using BCA, Bradford assays and SDS-polyacrylamide gel electrophoresis (PAGE) with alkaline protease treatment conditions including temperature and pH. The optimum condition of alkaline protease treatment for silkworm powder was found to be $60^{\circ}C$ and pH 7. The alkaline protease treatment resulted in increased contents of free amino acids, total polyphenol and total flavonoid compared to control group. The silkworm hydrolysates showed excellent antioxidant activities in various in vitro models such as 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2 - azino-bis(3-ethylbenzthiazoline-6)-sulfonic acid (ABTS) radical scavenging activity. These results provide useful information for using silkworm powder as an ingredient in functional foods and for exploiting alkaline protease treatment to improve the extractability and bioactivity of a raw material.

• 한국재료학회지
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• 제33권4호
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• pp.135-141
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• 2023

The volatilization of alkali ions in (K,Na)NbO₃ (KNN) ceramics was inhibited by doping them with alkaline earth metal ions. In addition, the grain growth behavior changed significantly as the sintering duration (t_s) increased. At 1,100 ℃, the volatilization of alkali ions in KNN ceramics was more suppressed when doped with alkaline earth metal ions with smaller ionic size. A Ca²⁺-doped KNN specimen with the least alkali ion volatilization exhibited a microstructure in which grain growth was completely suppressed, even under long-term sintering for t_s = 30 h. The grain growth in Sr²⁺-doped and Ba²⁺-doped KNN specimens was suppressed until t_s = 10 h. However, at t_s = 30 h, a heterogeneous microstructure with abnormal grains and small-sized matrix grains was observed. The size and number of abnormal grains and size distribution of matrix grains were considerably different between the Sr²⁺-doped and Ba²⁺-doped specimens. This microstructural diversity in KNN ceramics could be explained in terms of the crystal growth driving force required for two-dimensional nucleation, which was directly related to the number of vacancies in the material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.581-584
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• 2001

For the first time, a totally solid state electric double layer capacitor has been fabricated using an alkaline polymer electrolyte and an activated carbon powder as electrode material. The polymer electrolyte serves both as separator as well as electrode binder. The capacitor has a three-layer structure; electrode-electrolyte-electrode. A cyclic voltammetry and constant current discharge have been used for the determination of the electro chemical performance of capacitors.

• Journal of the Korean Wood Science and Technology
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• 제22권3호
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• pp.32-38
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• 1994

The methods in wood processing are so limited at present that a scope of its utilization is restricted. This often makes wood itself less valuable as a material comparing with other materials, that is, plastics, metals, and glass. Such differences are due to a lack of plasticity in wood, i.e. it cannot be melted, dissolved, or softened sufficiently for molding. However, once plastic properties are added to wood, it becomes more useful material. This further broadens the method in wood processing to a variety of fields. In this way, wooden material which is limited in use can be modified into a high quality product with additional value. Furthermore, utilization of wastes from wood, for example, would be made viable. In this study, thermoplasticization was carried out by benzylation of wood(sawdust). Various factors those affect the reaction were tested to produce benzylated wood with different degrees of substitution. Reaction temperature and time were the quite important factors. Optimum reaction temperature was 110$^{\circ}C$, and weight percent gains(WPG) of final products increased gradually with the increase of reaction time. The pretreatment (or preswelling) of wood with alkaline solution had a critical effect on benzylation. and the concentration of alkaline solution should be above 30% to obtain high weight percent gain. The thermal flow temperature of the benzylated wood decreased with the increase in weight percent gain, that of 80% weight percent gain is about 200$^{\circ}C$.

• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.453-466
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• 2008

Purpose: The purpose of this research is to study about initial adhesion, proliferation and activation of osteoblast to titanium surface treated with machined, hydroxyapatite coating, resorbable blast material blasting and anodizing method. Material and Methods: After treating the titanium surface of each block with machined, impurities were removed and sterilized. The number of cells attached from cultured osteoblast of respective experimental groups were measured at 1, 4, 7, and 14day and alkaline phosphatase, calcium, and inorganic phosphate concentration of cultured solution was measured. Result: Anodizing group showed the highest rate of cell attachment and proliferation activity. RBM treated group showed the highest increasing on their alkaline phosphatase activity, on the calcium apposition, on inorganic phosphate apposition of 1 and 4 days in cultured osteoblast to compare with other groups. Conclusion: On the basis of these findings, we conclude that surface modification of titanium was profoundly effected on the attachment, proliferation and activation of osteoblast in initial stage osseointegration.

• 자원리싸이클링
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• 제27권6호
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• pp.3-10
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• 2018

텅스텐은 고융점금속으로 주로 초경합금으로 사용되고 있다. 알칼리용액에서 텅스텐은 $WO{_4}^{2-}$로 존재하는데 용액의 pH가 감소함에 따라 중합반응이 일어나며 텅스텐산으로 침전된다. 따라서 원광석 및 2차 자원으로부터 텅스텐 회수를 위한 습식 제련 기술은 산침출과 알칼리침출로 대별된다. 2차 자원에 함유된 금속의 종류와 함유량 및 텅스텐의 소재화를 고려해서 2차 자원으로부터 텅스텐을 고순도로 회수하기 위한 공정을 선택해야 한다.

• 에너지공학
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• 제23권3호
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• pp.241-246
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• 2014

본 연구는 바이오에탄올을 생산하고자 대표적인 임업부산물인 낙엽을 바이오매스로 하여 전처리 과정을 거친 후 효소가수분해 공정을 적용하여 당화반응 특성을 비교 하였다. 전처리 방법은 화학적으로 산(HCl), 알칼리(NaOH, $NH_3$)처리하였고 각각 침지법, 교반법, 고압멸균법을 적용하여 실험하였다. 처리 효율은 효소가수분해 진행 후 포도당 생산량으로 확인하였다. 실험결과, 알칼리 전처리에서는 산 전처리 대비 18% 높은 글루코즈 생산량을 보여 바이오에탄올 생산을 위한 임업폐기물 화학적 전처리 방법으로는 알칼리처리가 효율이 더 높은 것으로 확인되었다. 또한 화학적 처리방법 중 각 방법을 적용하여 비교한 결과, 모든 방법이 알칼리-수산화나트륨 처리하였을 때 가장 높게 나왔다. 본 연구의 결과를 바탕으로 목질계 바이오매스 중 하나인 낙엽을 기질로 전처리 및 효소가수분해 공정의 가능성을 확인하였고 차후 바이오에탄올 생산에도 영향을 미칠 것으로 예상된다.