Ti has received considerable attention for aerospace, vehicle, and semiconductor industry applications because of its acid-resistant nature, low density, and high mechanical strength. A common precursor used for preparing Ti materials is TiCl4. To prepare high-purity TiCl4, a process based on the removal of VOCl3 has been widely applied. However, VOCl3 removal by distillation and condensation is difficult because of the similar physical properties of TiCl4 and VOCl3. To circumvent this problem, in this study, we have developed a process for VOCl3 removal using Cu powder and mineral oil as purifying agents. The effects of reaction time and temperature, and ratio of purifying agents on the VOCl3 removal efficiency are investigated by chemical and structural measurements. Clear TiCl4 is obtained after the removal of VOCl3. Notably, complete removal of VOCl3 is achieved with 2.0 wt% of mineral oil. Moreover, the refined TiCl4 is used as a precursor for the synthesis of Ti powder. Ti powder is fabricated by a thermal reduction process at 1,100oC using an H2-Ar gas mixture. The average size of the Ti powder particles is in the range of 1-3 μm.

In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M HNO3, a reaction temperature of 75℃, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, NaBH4 and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

Glass-ceramics were developed many years ago and have been applied in many fields such as electronics, chemistry, optics, etc. Much is already known about glass-ceramic technology, but many challenges in glass-ceramic research are still unresolved. Recently, large amounts of slag have steadily increased in the steel industry as by-products. To promote recycling of industrial waste, including steel industry slags, many studies have been performed on the fabrication of basalt-based highstrength glass-ceramics. In this study, we have fabricated such ceramics using various slags to replace high performance castbasalt, which is currently imported. Glass-ceramic material was prepared in similar chemical compositions with commercial cast-basalt through a pyro process using slags and power plant by-product (Fe-Ni slag, converter slag, dephosphorization slag, Fly ash). The properties of the glass-ceramic material were characterized using DTA, XRD, and FE-SEM; measurements of compressive strength, Vicker’s hardness, and abrasion were carefully performed. It is found that the prepared glass-ceramic material showed better performance than that of commercial cast-basalt.

Spherical fine cobalt powders were fabricated by new liquid reduction method. Commercial cobalt sufate heptahydrate was used as raw material. Also ethylene glycol was used as solvent and hydrazine-sodium hypophosphite mixture was used as reduction agent for the new liquid reduction method. A plate shaped cobalt powders with an approximately 300 nm were prepared by a traditional wet ruduction method using distilled water as solvent and hydrazine. Spherical fine cobalt powders with an average size of 1-3 μm were synthesized by a new liquid reduction method in 0.3M cobalt sulfate and 1.5M hydrazine-0.6M sodium hypophosphite mixture at 333K.

본 연구는 자몽종자추출물이 도포 포장지의 항균활성에 미치는 영향을 알아보았다. 저장 안전성 중 항균력을 확인 하기 위하여 그람 양성균(B. cereus, L. monocytogenes) 2종 과 그람 음성균(E. coli, S. enteritidis) 2종을 선택하였다. 자몽종자추출물의 농도별(60-5,000 ppm)에 따른 그람 양성 균의 투명환 크기는 최저 5 mm에서 최고 21 mm로 나타내 었다. 또한 그람 음성균의 투명환 크기는 최저 0 mm에서 최고 7 mm로 나타내었다. 자몽종자추출물을 농도별(60- 5,000 ppm)로 도포 포장시킨 경우 그람 양성균의 투명환 크기는 최저 5 mm에서 최고 19 mm로 나타내었다. 또한 그람 음성균의 투명환 크기는 최저 7 mm에서 최고 11 mm 로 나타내었다. 자몽종자추출물을 처리한 도포 포장지를 이용하여 즉석섭취 식품에 대한 저장 안정성을 알아본 결 과, GFSE의 농도(1,000, 5,000, 10,000 ppm) 차이에 따라 각각 11시간, 16시간, 18시간 동안 신선도가 유지 되었고, 일반 세균수 측정 결과, 1,000, 5,000 ppm 및 10,000 ppm 에서 각각 4.5 log CFU/g, 4.8 log CFU/g, 4.2 log CFU/g로 측정되어 저장성을 증가 시킴을 알 수 있었다.

Cobalt coated tungsten carbide-cobalt composite powder has been prepared through wet chemical reductionmethod. The cobalt sulfate solution was converted to the cobalt chloride then the cobalt hydroxide. The tungsten carbidepowders were added in to the cobalt hydroxide, the cobalt hydroxide was reduced and coated over tungsten carbidepowder using hypo-phosphorous acid. Both the cobalt and the tungsten carbide phase peaks were evident in the tungstencarbide-cobalt composite powder by X-ray diffraction. The average particle size measured via scanning electron micro-scope, particle size analysis was around 380 nm and the thickness of coated cobalt was determined to be 30~40 nm bytransmission electron microscopy.

곡류, 두류, 어패류분말, 건조채소류 및 다류 등 5가지 식품유형에 대하여 전자선과 감마선 0-10 kGy 조사 후 광자극발광법(PSL)과 열발광법(TL) 분석을 통해 적용 가능성을 확인하고 두 선종의 결과를 비교·분석 하였다. PSL 분석 결과, 새우분말을 제외한 비조사 검체는 700 이하의 PCs, 음성검체로 나타났다. 전자선과 감마선 조사된 곡류, 두류 및 다류는 양성검체뿐만 아니라 중간검체, 음성검체로도 확인되어 적용 가능성이 낮았다. 특히, 두류는 감마선보다 전자선 조사된 검체가 더 명확한 판별이 가능하였 다. 전자선과 감마선 조사된 어패류분말과 건조채소류는 모두 양성검체로 나타나 조사선원에 관계없이 조사여부 확인이 가능하였다. TL 분석 결과 조사되지 않은 검체는 자연방사선에 의해 300oC 전후에서 낮은 peak를 가지는 글로우곡선이 나타났고, 대부분의 조사 검체에서는 150- 250oC의 부근에서 특유의 글로우곡선이 나타났다. 하지만, 쌀과 레몬홍차는 조사에 따른 특이적인 peak가 나타나지 않아 조사여부 확인이 어려웠다. 또한 TL 비를 산출해본 결과, 쌀과 레몬홍차를 제외한 대부분 비조사 검체는 0.0001- 0.0728, 전자선과 감마선 조사된 검체는 0.1004-4.6748로 나타나 조사여부를 확인할 수 있었다. 쌀과 레몬홍차의 TL 비는 0.1 이하로 나타나 글로우 1에서 확인한 것처럼 조사여부를 판단하기 어려웠다. 따라서 조사 선원에 따른 곡 류와 두류의 PSL 측정 결과는 전자선 조사된 검체가 더 명확한 판별이 가능하였고, TL 측정 결과는 쌀과 레몬홍차를 제외하고 모든 검체에서 조사 선원에 관계없이 조사 여부 판별이 가능하였다. 본 연구를 통해 전자선 조사에 따른 확인시험법 적용 가능성을 확인하고 선종에 따른 PSL 시험법에 대한 검지감도의 차이를 확인하였다. 연구결과는 전자선 추가 허용에 따른 데이터베이스 구축 및 조사 식품 관리체계 마련에 기초자료로 활용될 계획이다.

The objective of this study was carried out to evaluate the efficiency of sperm collection methods on the post-thaw viability of cat semen. The cat semen was collected by artificial virginal (AV) and electronic ejaculate (EE) methods. The composition of semen extender was consisted of Tris-buffer supplemented with 20% egg yolk and 1% P/S antibiotics in Ext I, and more added 8% glycerol, 1.0% Equex STM paste of total volume in Ext II. The collected semen was adjusted the concentration and then diluted in Ext I for optimal concentration. The diluted semen was cooling to 5℃ temperature in refrigerator for at least 2 hrs and then diluted stepwise with Ext II for at least 1 hrs. After an equilibration for 1 hrs, the cooled semen was packaged in 0.5 ml straw and then freezing on the LN2 vapor over 5 cm above from LN2 and then immersed directly in LN2 for cryopreservation. The frozen semen was thawed in 38℃ water for 15 sec and then evaluated the motility, viability, and morphology. Post-thaw semen were calculated the motility by SMI (sperm motility index). The live-dead sperm was evaluated by Eosin-B and morphological evaluation was by Diff-quik kit staining. The post-thaw concentration (89×106 /ml vs. 128×106 /ml), viability (22.6±10.6% vs. 37.1±26.1%), morphological normality (27.0±50.2% vs. 45.6±123.0%) of EE and AV groups were not significant different, but the post-thaw motility was significant lower in EE than that in AV group (53.1±3.6 vs. 73.6±5.7) (p<0.05). In conclusion, semen collection methods did not significant different between EE and AV groups except of post-thaw motility and so both semen collection methods could be applied in feline semen collection methods.

A Ni-based superalloy is widely used in many industrial field because of their high performance which is unusual class of metalic materials with an exceptional properties (high temperature strength, toughness, stress, oxidation/corrosion resistance). So, the most important application of Ni-superalloy is aircraft engines (gas turbine, turbine blade, etc), gas turbines for power generation and other challenging environments such as nuclear power and chemical plants. In the future, according to increasing the demand, amount of waste turbine blade is expected to be discarded. Therefore, it is necessary to research about recycling technology of waste Ni-based superalloy. In this study, we focused our research on the possibilities of recycling using waste Ni-based superalloy by AOD (argon-oxygen decarburization) process. Also, we were investigated experimental changes including Ar or O2 flow rate, reaction time, voltage to obtain the data of element component and structural changes. So, we evaluated the possibility about recovery of Ni or other metals.

In Korean steel making industry is generating 25 billion tons of slag as industrial by-products per year. Uses of these slags to manufacture high functional abrasive material are of greater feasible option for sustainable development of industry as well as effectively solve the pollution issue associated with these waste. Recycling methods of slag have been actively studied for decades, but most of the slag recycling methods studied are related to low cost building materials. Recently, several combinations of by-products have been used in glass-ceramic manufacturing, mostly the abrasive materials are basalt based glass-ceramic. Using these industrial by-products instead of natural basalt ores, high functional product can be manufactured. This piece of investigation focused on the feasibility study for producing the basalt based glass-ceramic from recycled industrial by-products only, without any natural materials as raw materials. By controlling various process parameters like, mixture ratios of materials, heat treatment for casting, and soaking basalt based glass-ceramic were prepared. The prepared materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), thermo-gravimetry and differential thermal analysis (TG-DTA). Excellent material properties were observed.