• Journal of the Korean Chemical Society
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• v.37 no.10
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• pp.867-873
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• 1993

Influences of crystallization time and $H_2O/Al_2O_3$ ratio of the reaction mixtures on the synthesis of AlPO$_4$-5 molecular sieve have been studied by X-ray powder diffraction, nitrogen adsorption, scanning electron microscope (SEM), and solid state $^{27}$Al magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. The degree of crystallinity of AlPO$_4$-5 follows a sigmoid pattem as crystallization time increases. The induction period is shorter than 1 h when the crystallization process is carried out at 150$^{\circ}$C. The conversion of reactants to product, AlPO$_4$-5, can be clearly observed, and all of the determined physical properties change abruptly after about 2 h. It is found that increase in $H_2O/Al_2O_3$ ratio of the reaction mixtures not only changes the crystal morphology from aggregates to hexagonal single crystals, but also results in the formation of longer AlPO$_4$-5 crystals.

• Journal of Soil and Groundwater Environment
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• v.19 no.1
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• pp.1-7
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• 2014

When processing the biomass by Hydrothermal carbonization (HTC), a slow pyrolysis process, it produces bio-gas, biooil, and biochar. Among these end products, biochar is known for isolating or storing carbon and being used as a soil amendment. In this study, the characteristics of biochar generated by HTC at $250^{\circ}C$ for 1 hour, 2 hours, 3 hours, and 20 hours with synthetic food wastes and wood wastes were analyzed for potential uses in soil contaminated with heavy metals. The yield of biochar (weight %) increased when the ratio of wood wastes increased and showed a decreasing tendency as reaction time increased. Elemental analysis of biochar based on various conditions showed a maximum of 70% carbon (C) content. The carbon content showed an increasing tendency with the increase of wood wastes. Iodine adsorption test was peformed to determine the optimum reaction condition, which was 15% wood waste for mixing ratio and 2 hours for reaction time. Using biochar generated at the optimum condition, its capability of adsorbing heavy metals (Cd, Cu, Pb, Zn, Ni) was evaluated. It was concluded that lead (Pb) was removed efficiently while zinc (Zn) and nickel (Ni) were hardly adsorbed by biochar.

• Korean Journal of Pharmacognosy
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• v.41 no.3
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• pp.204-209
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• 2010

Osteoporosis is a metabolic bone disease associated with an imbalance of bone remodeling. Osteoporosis is characterized by decreased bone mass and increased bone fractures. In this study, we investigated the effects of horse bone extracts (HBEs) in vivo. Horse bone was extracted with 80% alcohol (HBE-A) at $100^{\circ}C$ or water (HBE-W) at $120^{\circ}C$. Animal model of postmenopausal osteoporosis was used, in which osteoporosis was induced by ovariectomy of female S.D. rats (female rats were divided into 5 groups), and HBEs were administered to ovariectomized rats every day for 8 weeks. After 8 weeks, the rats were sacrificed and the following osteoporotic factors were measured: body weight, bone mineral density (BMD), uterine/body weight ratio, serum estradiol (E2), and serum alkaline phosphatase (ALP). The results showed that the administration of HBE-W decreased the changes of body weight in ovariectomized rats. HBE-W increased the uterine/body weight ratio and BMD. In addition, HBEs decreased the ALP. Therefore, HBEs may be used for the prevention or treatment of bone disease.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.482-488
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• 2007

The optimum conditions for the extraction of lecithin from egg yolk were determined using response surface methodology (RSM). On the basis of the results of preliminary experiments, the most effective values were selected. The effects of three independent variables, dilution ratio, solvent composition, and extraction temperature on the response of crude egg lecithin (g) were then determined. The optimum conditions for egg lecithin separation obtained using ridge analysis were 6.51, 95.83%, and $40.2^{\circ}C$ for the dilution ratio, solvent composition, and extraction temperature, respectively. Using the optimum conditions, 55.04% of crude lecithin in total phospholipid can be obtained from 100 g liquid egg yolk. The experimental values (56.21% crude lecithin in total phospholipid) agreed with the predicted values.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.642-651
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• 1996

The purpose of this study was to evaluate the relationship between monomer compositions and the changes in the degree of conversion in the various layers of composites after additional heat curing. Four types of composites and 3 types of inlay ovens were used in this study. Composite was placed in a 4-mm thick teflon mold, and light cured from the top for 60 seconds. Ten samples were prepared for each composite ; 5 of these were additionally heat cured in an inlay oven as the manufacturer recommended. After light curing or light and heat curing, the samples were sectioned into four parts and assigned to groups A, B, C, or D according to their distance from the light source. These sections were then thinned to 50-$70{\mu}m$, and these wafers were analyzed with a Fourier Transform Infrared Spectrometer(FI-IR) to determine the degree of conversion. A standard baseline technique was used to calculate the degree of conversion. $^{13}C$ NMR spectra of bis-GMA, TEGDMA and bis-EMA, were acquired using a Varian Gemini spectrometer operated at 200 MHz. $CDCl_3$ solvent was used for qualitative analysis. The degree of conversion was affected by bis-GMA : TEGDMA ratio but it seemed to be also affected by other factors. When the composites were heat cured, significant increases in the degree of conversion were noted throughout the samples, but the amount of increase differed between materials. Thus, clinical performance of a heat-treated composite inlay may be different depending on materials.

• Journal of electromagnetic engineering and science
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• v.6 no.2
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• pp.83-91
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• 2006

In this paper, we develop space-time(ST) Rake receivers for Time Division Synchronous Code Division Multiple Access(TD-SCDMA) base stations(BS). The beamforming of BS transforms the uplink MIMO channel space into many sub-sectors' channels to be nearly orthogonal, thus, well established 1-D Rake technology can be used to TD-SCDMA base station to construct ST Rake, which simplified the system's implementation as well as enlarged users' capacity by the beamforming. The construction and capacity of MIMO sub-sectors by multi-beamforming have been presented. The proposed ST Rake algorithm include the multi-beamforming algorithm for MIMO sub-sectors and classical 1-D Rake algorithm. The calculating formulas for interference plus noise ratio(SINR) and bit error rate(BER) have been derived. Simulations verify that the proposed ST Rake receiver for BS is effective, and the BS systems can get higher system capacity and can be of better performance than presented TD-SCDMA systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12C
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• pp.1217-1224
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• 2003

In this paper, we propose an edge side-lobe suppressor (ESS) for the uplink of OFDMA systems, which mitigates the interference introduced by different frequency offsets between a desired user and the other users. We evaluate the proposed ESS scheme by measuring average signal to interference ratio (SIR) and average bit error rate (BER). The simulation results confirm that the proposed ESS scheme improves system performance by approximately 5∼10 dB SIR as compared to conventional OFDMA systems. Because the additional operations for the proposed scheme can be performed by a real-valued look-up table, the implementation of the ESS hardly requires increasing transmitter and receiver complexity.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.667-670
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• 1996

Four Murrah male buffalo calves with an average body weight of $188{\pm}1.6kg$ each fitted with rumen and abomasal cannula were subjected to defaunation followed by refaunation. The animals were offered wheat straw and a concentrate mixture. There was no difference in dry matter, starch and nitrogen intake in defaunated and refaunated buffalo calves. Production of ruminal total volatile fatty acid and acetate : propionate ratio decreased (p < 0.01) whereas, molar proportion of propionate increased (25.8 Vs 19.4% p < 0.01) in defaunated animals. Fermentation of starch in rumen increased (73.9 Vs 65.8%, p < 0.01) but in small intestine decreased (20.2 Vs. 28.2%, p < 0.05) in defaunated calves. The flow of non ammonia nitrogen (NAN) to abomasum (75.1 vs 68.6 g/d, p < 0.01) and its digestion in small intestine (37,6 vs 32.5 g/d, p < 0.01) was improved due to defaunation. However, No difference in the total tract digestibility of starch and nitrogen was found in defaunated and refaunated buffalo calves.

• Carbon letters
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• v.24
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• pp.28-35
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• 2017

We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1257-1262
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• 2008

A long-distance remote sensing of temperature and current based on a fiber Bragg grating (FBG) is proposed and demonstrated. The thermal expanding effect of the epoxy and the Er-doped fiber ring laser (EFRL) are applied to the sensor system to enhance the temperature and current sensitivity. An EFRL with a 5 km-single-mode fiber and a FBG shows a high extinction ratio of more than 60 dB and a low power fluctuation of less than 1 dB. The metal wires are used to supply the current to the sensors. When the NOA65 puts on the FBG as a thermal expanding material, the temperature and current sensitivity of the lasing wavelength shift are about $30\;pm/^{\circ}C$ and 3pm/mA, respectively. The proposed sensing scheme is useful for measurement of current or temperature at a distant object of more than several km.