Cemented tungsten carbide has been used in cutting tools and die materials, and is an important industrial material. When the particle size is reduced to ultrafine, the hardness and other mechanical properties are improved remarkably. Ultrafine cemented carbide with high toughness and hardness is now widely used. The objective of this study is synthesis of nanostructured WC-Co powders by liquid phase method of tungstate. The precursor powders were obtained by freezen-drying of aqueous solution of soluble salts, such as ammonium metatungstate, cobalt nitrate. the final compositions were WC-10Co. In the case of liquid phase method, it can be observed synthesis of WC-10Co. The properties of powder produced at various temperature, were estimated from the SEM, BET and C/S analyser.

Nanostructured cobalt materials have recently attracted considerable attention due to their potential applications in high-density data storage, magnetic separation and heterogeneous catalysts. The size as well as the morphology at the nano scale strongly influences the physical and chemical properties of cobalt nano materials. In this study, cobalt nano particles synthesized by a a polyol process, which is a liquid-phase reduction method, were investigated. Cobalt hydroxide (Co(OH)2), as an intermediate reaction product, was synthesized by the reaction between cobalt sulphate heptahydrate (CoSO4·7H2O) used as a precursor and sodium hydroxide (NaOH) dissolved in DI water. As-synthesized Co(OH)2 was washed and filtered several times with DI water, because intermediate reaction products had not only Co(OH)2 but also sodium sulphate (Na2SO4), as an impurity. Then the cobalt powder was synthesized by diethylene glycol (DEG), as a reduction agent, with various temperatures and times. Polyvinylpyrrolidone (PVP), as a capping agent, was also added to control agglomeration and dispersion of the cobalt nano particles. The optimized synthesis condition was achieved at 220˚C for 4 hours with 0.6 of the PVP/Co(OH)2 molar ratio. Consequently, it was confirmed that the synthesized nano sized cobalt particles had a face centered cubic (fcc) structure and with a size range of 100-200 nm.

The pomegranate (Punica granatum), especially its fruit, possesses a vast ethnomedical history and represents a phytochemical reservoir of heuristic medical value. The tree and fruit can be divided into several anatomical compartments, and the fruit juice, peel and oil are known to be weakly estrogenic and heuristically of interest for treatment of menopausal symptoms and sequellae. In this study, analysis of estrogen in pomegranate extract was carried out with LC/MS/MS. Three batches of pomegranate extract samples were used to analysis the target compounds (estrogen). The contents of estrogen derivatives in the samples were 38.6 ppb of estriol, 83.5 ppb of estrone,and 10.9 ppb of estradiol. This result suggests that the pomegranate extract can used for treatment of menopause symptoms in the woman.

가스상의 체적분율과 압력강하는 기액이상류에 대한 이해와 예측에 있어서 매우 중요한 인자이다. 또한 그것들은 산업용 대용량의 열교환시스템 및 선박에 설치되는 보일러 및 냉동시스템의 설계에 있어서 필수적인 항목이다. 따라서 본 논문에서는 파이프의 모든 경사각도에서 기액이상류 가스상의 체적분율과 압력손실을 예측할 수 있는 이론적 해석 방법을 제시한다. 여기서의 이론적 해석은 2유체 층상류 모델을 기초로 하고 있다. 또한 이론적 해석결과와 기존의 실험결과와 비교한 결과에 대해서도 제시한다.

For the fabrication of core-shell structure bimetallic lead-free solder balls, both the critical temperature (Tcr) for the phase separation of two immiscible liquid phases and the temperature coefficient of the interfacial tension between the two separated liquid phases are required. In order to obtain this information, the temperature dependence of the surface tension of 60%Bi-24%Cu-16%Sn(-REM) alloys was measured using the constrained drop method. The slope of the temperature dependence of the surface tension changed clearly at a critical temperature for the separation of two immiscible liquid phases. The critical temperature of the 60%Bi-24%Cu-16%Sn alloy was estimated to be 1097K. An addition of 0.05% Ce decreased the critical temperature to 1085K, whereas that of 0.05% La increased it to 1117K. It was found that the surface tension and its temperature coefficient of the 60%Bi-24%Cu-16%Sn alloy were slightly increased by the addition of 0.05% Ce and 0.05% La. In addition, additions of Ce and La increased the temperature coefficient of the interfacial tension.

Nanostructured carbon materials have been found to have applications in fuel cell electrodes, field emitters, electronic devices, sensors and electromagnetic absorbers, etc. Especially, the CNF (carbon nanofiber) can be expected to play an important role in catalyst supporters for fuel cell electrodes and chemical reactions. In this study, we synthesized CNF from a liquid phase carbon source by a solvothermal method. In addition, we studied the parameters for the preparation of CNF by controlling heating and cooling rates, synthesis temperature and time. We characterized the CNF by SEM/TEM, XRD, Raman spectroscopy and EDS. We found that the heating and cooling rate have strong effects on the CNF formation and growth. We were able to prepare the best CNF at the heating rate of 10˚/min, at 450˚ for 60 minutes, and at the cooling rate of 4˚/min. As a result of Raman spectra, we found that the sample showed two characteristic Raman bands at ~1350cm-1 (D band) and ~1600cm-1 (G band). The G band indicates the original graphite feature, but the D band has been explained as a disorder feature of the carbon structure. The diameter and length of the CNF was about 15~20nm, and over 1μ, respectively.

In recent years, the number of complaints about indoor air pollution caused by volatile organic compounds(VOCs) has increased. It is important that evaluating and understanding emission of indoor air pollutant from building materials. The aim of this study was to evaluate emission test methods for liquid phase building materials such as paint, adhesive and sealant, and to determine the emission of total volatile organic compounds(TVOC) from liquid phase building material. The quantity of TVOC emission was measured by a gas chromatography/mass spectrometry (GC/MSD). It was found that liquid phase building materials were classified according to their use and ingredient. The TVOC concentration from oil-based paint was the highest among 8 groups of test materials. The unidentified volatile organic compounds occupied 83.0% of TVOC emission from test materials. The aliphatic hydrocarbons and aromatic hydrocarbons occupied 7.2%, 6.9% of TVOC, respectively. The concentration of TVOC decreased by an increase during emission test period. After 3 days, the concentration of TVOC from paint, adhesive and sealant were about half of the concentration at the first day. The ratio of concentration between 7 days and 1 day was 0.11～0.15 from water-based paint and 0.46～0.48 from epoxy adhesive.

In this study, the diffusion behaviors of C and Co in liquid phase sintering of WC-Co system were investigated whether these two components diffused in the same direction in case of having opposite gradient each other with not being phase. The green compacts with controlled compositions in not being of phase and gradient composition which one is WC-5Co-1.2%C, the other is WC-XCo-0.2%C (where X = 5, 10, 15, 20, 25) were sintered at and and then the diffusion behaviors of C and Co were investigated by analyses of compositional change, also determined for microstructure and microhardness. Also, same testing was carried out on the specimens with dual layers sintered in upright and reverse positions to evaluate the effect of gravity on the diffusion in liquid Co. From the results of this study, we can find the fact that the direction of diffusion for C and Co in WC-Co system during liquid phase sintering was different and the effect of gravity for the liquid was insignificant. Also other physical properties were changed on the diffusion of elements.

When an alloy such as Ni-W is liquid phase sintered, heavy solid W particles sedimentate to the bottom of the container, provided that their volume fraction is less than a critical value. The sintering process evolves typically in two stages, diffusiondriven macrosegregation sedimentation followed by true sedimentation. During macrosegregation sedimentation, the overall solid volume fraction decreases concurrently with elimination of liquid concentration gradient. However, in the second stage of true sedimentation, the average solid volume fraction in the mushy zone increases with time. It is proposed that the true sedimentation results from particle rearrangement for higher packing efficiency.

Crushed peach stone shells were impregnated with H3PO4 of increasing concentrations (30-70%) followed by heat treatment at 773 K for 3 h. Produced carbons (ACs) were characterized by N2 adsorption at 77 K using the BET-equation and the α-method. High surface area microporous ACs were obtained, with enhanced internal pore volume, as function of % H3PO4. Adsorption isotherms from aqueous solution were determined for methylene blue (MB) and p-nitrophenol (PNP), as representatives for dye and phenolics pollutant molecules. Application of the Langmuir model proved the high limiting capacity towards both solute molecules, MB was uptaken in increasing amounts as function of H3PO4 concentration and generated porosity. High removal of PNP was almost the same irrespective of porosity characteristics. Competitive adsorption of H2O molecules on the hydrophilic carbon surface seems to partially reduce the available area to the PNP molecules. Application of the pseudo-second order law described well the fast adsorption (≤ 120 min) at two initial dye concentrations.