• KSBB Journal
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• v.20 no.5 s.94
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• pp.359-362
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• 2005

Bacillus licheniformis was an useful material for improvement of fecal microflora. The stability of Bacillus licheniformis in low pH (pH 2, 3, 4, 6, 7), artificial bile acid, high concentration of salt (0, 5, 10, 20, $30\%$), and ethanol (0, 4, 8, 16, $32\%$) was investigated in this study. The viability of Bacillus licheniformis was stable for pH 3, 4, 6, 7 Final viability of Bacillus licheniformis was confirmed below $25\%$, in the bile acid. In high concentration of salt, Bacillus licheniformis showed optimal viability in $10\%$ of salt. The viability of Bacillus licheniformis was over $95\%$ in condition of ethanol concentration $4\%,\;8\%,16\%,\;32\%$ contrast with uncontained ethanol at $37^{\circ}C$ for 4h. It was verified that Bacillus licheniformis was stable for pH 4, 6, 7, high concentration of salt and ethanol but was unstable in pH 2 and bile acid.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1797-1806
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• 1998

Future satellite communication systems will be developed at Ka-band (20/30 GHz) owing to the relatively wide frequency allocation and current freedom from terrestrial interference for multimedia services. A serious disadvantage of the Ka-band, however, is the very high atmospheric attenuation in rainy weather. Synchronous CDMA drastically redces the effect of self-noise with several interesting features of CDMA for mobile communications such as fixible freuqncy rese, the capability of performin soft-handover and a lower sensitivity to interference. This paper evaluates the performance of a synchronous CDMA reture link for a Ka-band geostationary satellite communication system. For a fixed satellite channel whose characteristics depend on weather conditions, the signal envelope and phase for this channel is modelled as Gaussian. The bit error and outage probability, and the detection loss due to imperfect chip timing synchronization is analytically evaluated and the system capacity degaradation due to the weather condition is estimated. The two cases consist of the general case in which all users are affected by rain condition, and the worst case in which the reference user is only affected by rain attenuation. the results for two cases of rain condition clearly show that synchronous CDMA eases the power control requirements and has less sensitivity to imperfect power control.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.991-997
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• 2003

The effect of A1$_4$C$_3$ additive on the thermoelectric properties of SiC ceramics were studied. Porous SiC ceramics with 47∼59% relative density were fabricated by sintering the pressed $\alpha$-SiC powder compacts with A1$_4$C$_3$at 2100∼220$0^{\circ}C$ for 3 h in Ar atmosphere. Crystalline phases of the sintered bodies were identified by powder X-Ray Diffraction (XRD) and their microstructures were observed with a Scanning Electron Microscope (SEM). In the case of A1$_4$C$_3$ addition, the phase transformation of 6H-SiC to 4H-SiC could be observed during sintering. The Seebeck coefficient and electrical conductivity were measured at 550∼95$0^{\circ}C$ in Ar atmosphere. In the case of undoped specimens, the Seebeck coefficients were positive (p-type semiconducting) possibly due to a dominant effect of the acceptor impurities (Al, Fe) contained in the starting powder and electrical conductivity increased as increasing sintering temperature. Electrical conductivity of A1$_4$C$_3$doped specimen is larger than that of undoped specimen under the same condition, which might be due to the reverse phase transformation and increasing of carrier density. And the Seebeck coefficient of A1$_4$C$_3$ doped specimen is also larger than that of undoped specimen. The density of specimen, the amount of addition and sintering atmosphere had significant effects on the thermoelectric property.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.369-376
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• 2003

In this paper, Ka-Band NRD guide band pass filter with newly designed inductive post structure is proposed and analyzed with its test results. Generally, millimeter-wave filters are very sensitive in their physical dimensions, hence, it is requires extreme precisions of several micron so as to get the designed performance. In case of common NRD Guide filter with air gap coupled structure, it is fabricated with dielectric blocks coupled via air gap. In these structures, however, it was not easy to fabricate and to process of each NRD guide dielectric resonator blocks using PTFE, so it was almost impossible to assemble with several microns in precision. In this our research, however, each dielectric resonators are coupled with a pair of inductive metal post, so all resonators are located in a single NRD Guide. The dielectric parts between two pairs of posts are operated as resonators of each stage, and the positions of the post decide the couplings between resonators. The structure we suggested is suitable fur mass production, because it is very simple and easy to process. As a result of measurements, designed NRD guide inductive post filter has a superior performance. The center frequency is 39.475 GHz with 350 MHz bandwidth, insertion loss is less than 1.8 dB, and the return loss is below than -18 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.158-165
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• 2007

In this paper, the circularly polarized $4{\times}4$ array antenna is proposed for the X-band. A single antenna consists of square patch and unequal cross-aperture coupled feeding. The RHCP(Right Handed Circularly Polarization) is generated by unequal cross-aperture coupled feeding. By reducing space among elements of way antenna from 0.8 ${\lambda}_0$ to 0.45 ${\lambda}_0$, the mounting area of array antenna is miniaturized. The $2{\times}2$ array antenna is designed using sequential rotation feeding network. The good level of gain, axial ratio, and impedance bandwidth are achieved. The $4{\times}4$ array antenna is extended by ${\lambda}/4$ transformer and T-junction power divider. The simulated maximum radiation gain is 15.09 dBi at 10 GHz. The simulated 3 dB Axial Ratio bandwidth is from 9.05 to 10.4 GHz(13.5%). Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $4{\times}4$ array antenna is from 8.45 to 11.84 GHz(33.9%). The measured maximum radiation gain is 11.10 dBi at 10 GHz. The measured 3 dB Axial Ratio bandwidth is from 9.42 to 10.47 GHz(10.5%).

• Korean journal of communication and information
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• v.29
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• pp.233-269
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• 2005

The purpose of the study is to explore the characteristics of lawsuits against investigative reporting programs of the broadcast media. This study proposed three research questions: (1) what were the characteristics of court derisions on the investigative reporting programs? (2) what were the reasonings on which judges rely in the lawsuits for a right of reply? (3) what were the critical issues and how the libel laws were applied in balancing between the freedom of the press and the protection of individual rights. To answer these questions, the study employed quantitative and qualitative methods analysing 35 related cases. This study revealed that investigative reporting programs must deal with the Issues of 'public figures' and 'matters of public concern' to be protected under the freedom of the press. The study also found that the broadcast media must prove legitimate public interests and the truth of the facts to prevail in a case. In 1999, the Constitutional Court of Korea held that pubic figures in libel cases must be regarded differently from private figures. In accordance with the decision, the Supreme Court has applied differing criteria for public figures in libel cases. However, courts have not set a clear definition of the public figure yet. To advocate the freedom of the press, as the results of this study indicate, TV producers and journalists should behave lawfully in the course of newsgathering and provide the opportunities of reply for their news sources.

• Applied Biological Chemistry
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• v.30 no.2
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• pp.109-117
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• 1987

Three rice varieties of Akibare (japonica), Milyang 30 (indica) and Taebaeg (indica) were investiated for sensory and physical qualities of cooked rices during storage at the temperature range of $4^{\circ}C$ and $70^{\circ}C$ for 25 hours. The qualities studied were sensory attributes of odor, taste and appearance which were evaluated by multiple comparison method. The other properties were size of rice granule and separation Property of individual cooked rices in water. The sensory results showed that all of the descriptions except moldy odor and oily taste were scored higher values for cooked rices of Akibare than those values of Milyang 30 and Taebaeg. It was found that storage of cooked rices at various temperatures resulted a significant decrease in most of sensory qualities except moldy odor and oily taste which were rather increased. The quality change was more affected at storage at low temperature, particularly at $4^{\circ}C$, than at higher temperatures. The property of individual separation of cooked rices in water for freshly cooked rices showed that Akibare was separated 44.4% after 1 minute shaking while Milyang 30 and Taebaeg had the higher separation value of 53.1%, and 51.0%, respectively. This characteristic was noticeably reduced after 3 hours storage and then steady increased during further storage. It was also found that the separation percent was generality increased as the storage temperature increased from $4^{\circ}$ to $70^{\circ}C$.

• Applied Biological Chemistry
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• v.30 no.2
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• pp.118-125
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• 1987

Three rice varieties of Akibare (japonica), Milyang 30 (indica) and Taebaeg (indica) were investigated for their changes in sensory and physical qualities of cooked rices during storage at the temperature range of $4^{\circ}C$ and $70^{\circ}C$ for 25 hours, The qualities studied were sensory attributes of texture which were evaluated by multiple comparison method and physical characteristics of texture measured using with rheometer. Physical Properties of hardness, adhesiveness and elasticity of cooked rices were found to be different among the rice varieties and were affected by storage conditions. Higher values in hardness and elasticity and lower values in adhesiveness were measured for cooked rices of Akibare immidiately after cooking. Those physical values were changed by a steady decrease in hardness and elasticity and increase in adhesiveness during storage for 25 hours. Correlations between sensory and physical characteristics of texture was found a significant relationships between gumminess and hardness (r=0.696), gumminess and adhesiveness (r=-0.800) and gumminess and elasticity (r=0.806).

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.259-266
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• 2007

Enormous amount of zeolite by-products as a fine powder have been produced while manufacturing commercial zeolite products. Granulation of the zeolite by-products is necessary in order for them to be recycled as soil conditioners or absorbent for various environmental contaminants due to the limitations inherent from their physical properties. We granulated the zeolite powders using Portland cement as a cementing agent and characterized the physical and chemical properties of the granulated zeolite product. The experimental natural zeolite had a Si/Al ratio of 4.8 and CEC of 68.1 $cmol_c\;kg^{-1}$. The X-ray diffractometry (XRD) revealed that clinoptilolite and mordenite were the major minerals of natural zeolite. Smectite, feldspar and quartz also existed as secondary minerals. Optimum conditions of granulated zeolite production occurred when natural zeolite was mixed with Portland cement at a 4:1 ratio and granulated using the extruder, left to harden for one month at $25^{\circ}C$ and treated at $400^{\circ}C$ for 3 hours. The wide spectra of XRD revealed that the granulated zeolite had amorphous oxide minerals. The alkali- or thermal-treated natural zeolite exhibited pH-dependent charge properties. The major minerals of the granulated zeolite were clinoptilolite, mordenite and tobermorite. The buffering capacity and charge density of the granulated zeolite were greater than those of natural zeolite.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.83-104
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• 2012

The main purpose of tramp ships in shipping markets is to produce operation profits by minimizing the running days in a contract of the voyage charterparty. It is an especially difficult task for the owners to earn operation profits in the present recessional shipping market. Tramp ships are moving towards globalization in order to look for a variety of cargoes, which are distinguished from the liners operating regularly as per the fixed time schedule. Tramp shipping, therefore, requires special attention every voyage to secure operation efficiency which comes from minimized sea and laytime in port. The laytime is allowed by owners but if the charterers use more laytime than that which is incorporated in the charterparty, then a compensation known as 'demurrage' must be paid to owners. Conversely if the time is shorter this is called 'despatch' and in this case the owners are paid. As the laytime issue in the voyage charter is somewhat delicate, it often causes much disputes between charterers and owners during the cargo handling in ports. This study focuses on the charterers' right and duty on the laytime which is usually applied for the benefit of the charterers. Reference is also made to English law cases to reinforce this study and the conclusion will make relevant suggestions for further research.