• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.283-287
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• 1990

The study was aimed at investigating sintering characteristics, the overall properties from the ternary Li2O-Al2O3-SiO2 system. This system, which was considered without additives and selected five compositions, was studied with variation of the amount of SiO2. The reactivity of the system was observed by D.T.A.. Characteristics of sintering, microstructure, property and stability of produced phase were studied. It was found that because the range of sintering was narrow and the temperature of sintering was close to the melting temperature, the sintering by the general method was difficult. Also, these linear thermal expansion coeffecients were measured.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.483-489
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• 2006

In this paper, new wideband lens amplifiers are proposed for C-band wireless communication service. In order to obtain the wideband property, all components of the proposed lens amplifiers are designed with balanced structure and wideband characteristics. Fat dipole antenna as the input and output antenna, balanced amplifier as amplifying components, and coplanar stripline(CPS) as the delay line fer the beam focusing are used fur composing the stable wideband lens amplifier. The $5{\times}5$ 2D lens amplifier has the characteristics that the absolute gain is 7.5 dB, the EIPG is 37.4 dB at 6 GHz, and the 3-dB gain bandwidth is 19.8 %.

• Tunnel and Underground Space
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• v.7 no.3
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• pp.238-245
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• 1997

A transient pulse methos has been used to measure the permeability of Pocheon granite pre-heated from $25^{\circ}C$ to $600^{\circ}C$ at effective pressure up to 32MPa. The permeability of whole rock ranged from 0.72 $\mu$d at 10MPa to 0.20 $\mu$d at 32MPa. The permeability of rock heated to $600^{\circ}C$ ranged from 18.07$\mu$d at 10MPa to 6.39$\mu$d at 32MPa. Confining pressure has greater effects on the rocks thermally treated to lower thermal-cycle temperatures than on the higher thermally treated rocks. The increase of permeability is most pronounced between 40$0^{\circ}C$ and $600^{\circ}C$. Below 40$0^{\circ}C$, permeability increase is expected to be associated with the formation of new cracks and widening of preexisting cracks, whereas above 40$0^{\circ}C$, permeability increase is expected to reflect widening of cracks. Using the equivalent channel model, author shows that the exponent n in the relationship relating the permebility(k) to porosity($\phi$) by k∝$$\phi$^n$ falls in the range 2.7$\leq$n$\leq$3.0.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.357-362
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• 2000

Stable isotope ratios of oxygen and hydrogen were investigated in southern Yellow Sea in August 1997. Salinity showed good positive correlation with ${\delta}^{18}$O and ${\delta}$. The correlation between ${\delta}^{18}$O and ${\delta}$D is good. From the relationship between these parameters, we obtained two lines of conclusion: 1) seawater of study area I in summer is a mixture of Changjiang Water and modified Kuroshio Water; 2) stable isotopes are very useful tracers in studying property and behavior of water masses in the study area. In case when water masses can not be easily distinguished by T-S analysis, the stable isotopes seem to be powerful tools for this purpose.

• Journal of the Korean Society of Systems Engineering
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• v.5 no.2
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• pp.27-34
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• 2009

This paper analyze technical review entry criteria and review process based on system property, and review checklist to conform technical review is also showed. The execution of review is determined according to the preparation of review item and identification for risk element. Risk level should be mitigated before technical review by appropriate plan. This paper described the entering condition of technical review for developmental phase, and tailoring consideration for technical review condition. Described technical review entry criteria, review process, and tailoring consideration is applied to development of test equipment for ground ant-air missile system. Applied system specific technical review process, tailored entry condition for test equipment for ground ant-air missile system and review check list is showed and the effectiveness of described system specific technical review process is presented.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.350-356
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• 2009

The objection of this research is to conform of practicable possibility and recycling of producing junk after citrus fruits is processed. In the middle of practicable possibility, with verification of antibiosis that tactiling sensibility in a microorganism. With extracting d-limonene oil that have 70${\sim}$90% a component of oil out of junk citrus peel, making certain the about 12000ppm(1.2%) concentration of it. By means of antibiosis property over the a pathogenic bacterium as well as a residence bacterium, considerating the limit of application against daily living supplies needs to antibiosis. Antibiosis effect of a stationing bacterium in the body permanently and by means of antibiosis verification of special bacteria Propionibacterium Acnes that causative skin trouble is selected, in based the antibiotic sencitivity test check up result of minimal inhibitory concentration(MIC).

• Analytical Science and Technology
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• v.18 no.5
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• pp.381-385
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• 2005

The title compound, $\{H_2NCH_2CH_2NH_2CH_2CH_2\}\{Cu(H_2O)_6\}(SO_4)_2$, I, has been synthesized under solvo/hydrothermal conditions and their crystal structure analyzed by X-ray single crystallography. Compound I crystallizes in the monoclinic system, $P2_1/n$ space group with a = 6.852(1), b = 10.160(2), $c=11.893(1){\AA}$, ${\beta}=92.928(8)^{\circ}$, $V=826.9(2){\AA}^3$, Z = 2, $D_x=1.815g/cm^3$, $R_1=0.031$ and ${\omega}R_2=0.084$. The crystal structure of the piperazine templated Cu(II)-sulfate demonstrate zero-dimensional compound constituted by doubly protonated piperazine cations, hexahydrated copper cations and sulfate anions. The central Cu atom has a elongated octahedral coordination geometry. The crystal structure is stabilized by three-dimensional networks of the intermolecular $O_{water}-H{\cdots}O_{sulfate}$ and $N_{pip}-H{\cdots}O_{sulfate}$ hydrogen bonds between the water molecules and sulfate anions and protonated piperazine cations. Based on the results of thermal analysis, the thermal decomposition reaction of compound I was analyzed to have three distinctive stages.

• ETRI Journal
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• v.19 no.2
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• pp.48-58
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• 1997

Using high quality high-$T_c$ superconducting (HTS) YBCO thin films, we designed and fabricated 3-pole, 5-pole, and 7-pole lowpass filters consisting of microstrip transmission lines and open-stub lines. We measured the microwave response of the filters in the temperature range of T=85 K to 27 K. AtT=30 K, the observed inband insertion loss was 0.14dB and 0.02dB for the 5-pole and 7-pole filters, respectively. The cut-off frequency was 4.7 GHz for the 5-pole filter and 7.9GHz for the 7-pole filter. To the authors' knowledge, the measured inband insertion losses are the best values reported so far for the open-stub line type HTS multipole lowpass filters. The skirt property of the 5-pole filter showed a large improvement over that of the 3-pole filter as predicted from the simulation. We found that, to obtain a stable performance, the HTS multipole lowpass filters should be operated at the temperatures between 60% and 70% of $T_c$.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.631-635
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• 2004

The rapid development of digital media and communication network urgently brings about the need of data certification technology to protect IPR (Intellectual property right). This paper proposed a new watermarking method for embedding contents owner's audio signal in order to protect color image IPR. Since this method evolves the existing static model and embeds audio signal of big data, it has the advantage of restoring signal transformed due to attacks. Three basic stages of watermarking include: 1) Encode analogue ID owner's audio signal using PCM and create new 3D audio watermark; 2) Interleave 3D audio watermark by linear bit expansion and 3) Transform Y signal of color image into wavelet and embed interleaved audio watermark in the low frequency band on the transform domain. The results demonstrated that the audio signal embedding in color image proposed in this paper enhanced robustness against lossy JPEG compression, standard image compression and image cropping and rotation which remove a part of image.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.419-422
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• 2004

In this paper, we propose a new metric called "dynamic gamma" to quantitatively evaluate the dynamic temporal response of an LC display device. The widely-used response time and corresponding 3-D bar graphs cannot fully describe the dynamic characteristics of an LC panel [1], and using response time to compare different LC panels and assessing the dynamic features of LC panels is difficult. On the other hand, the new metric MPRT mixes an LC panel's slow temporal response with its hold-type display effect. The proposed new metric, dynamic gamma, and corresponding 2-D plots, are arguably more suitable for quantitatively characterizing the dynamic characteristics of an LC panel, so comparing two LC panels becomes easy. Furthermore, dynamic gamma has the unique property that it can be used to quantify the limitations/capabilities and to assess the effectiveness of an overdrive mechanism for a particular LCD. In the paper, two LC panels using different technology are analyzed and compared using this new metric.