• 한국수소및신에너지학회논문집
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• 제2권1호
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• pp.77-82
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• 1990

To investigate the effect of strains heat effect and thermal energy on the intrinsic degradation of $LaNi_5$, the changes of P-C-Isotherm curves under the condition of mainly applied one of the above factors were investigated. The revesible hydrogen storage capacity decreased by means of the hydrogenation at high temperature without cyclings or pressure induced cyclings with low thermal energy. The degree of degradation was more severe as the heat of hydrogenation reaction increased. Thus the intrinsic degradation of $LaNi_5$ depended upon lattice strain as well as thermal energy.

• 한국구조물진단유지관리공학회 논문집
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• 제8권2호
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• pp.177-183
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• 2004

적산온도은 시멘트 수화의 결과로서 시간이 경과함에 따라 콘크리트 강도가 얻어진다는 것으로 콘크리트의 강도는 시멘트의 수화반응과 관계가 있다. 시멘트의 수화반응은 온도와 경과시간에 큰 영향을 받는다. 따라서 본 연구에서는 콘크리트 강도예측에 있어서 양생시간과 온도의 함수인 적산온도와 고강도콘크리트 강도의 상관성을 검토하고자 하였다.

• Toxicological Research
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• 제23권1호
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• pp.47-53
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• 2007

Amygdalin is a cyanogenic glycoside which is commonly found in almonds, bamboo shoots, and apri-cot kernels, and peach kernels. Amygdalin was first hydrolysed into prunasin, then degraded into cyanohydrin by sequential two-stage mechanism. The objective of this study was to examine the amygdalin decomposition and cyanide formation at various in vitro conditions, including acid, enzyme and anaerobic microbes (AM) in human feces (HF). In acid hydrolysis mimicking gastric environment, amygdalin was degraded to cyanide up to 0.2% in specific pH. In contrast, enzyme assay showed higher cyanide generation either by ${\beta}$-glucosidase, or by incubation with microbe. In conclusion, we are convinced of cyanide generation are occurred mainly by microbiological activities of the gut flora up to 41.53%. After ingestion with some staff, the degree and site of degradation in an organism is a key parst of regulatory decision making of that staff.

• 터널과지하공간
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• 제8권1호
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• pp.53-66
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• 1998

Considering the mechanical cracking in the concrete lining of tunnels occurring in relatively short period of time after the construction, there is a need for the study on the mechanical behavior and the cracking characteristics of double lining support system(shotcrete and concrete lining). For the proposed study, downscaled lining models of Kyung-Bu High Speed Railway tunnels were tested. Most longitudinal cracks at about 93 percentage developed within 30 arch degree from the vault. Cracking load was about 30 percentage of the failure load and the deflection under the cracking load was 10 percentage of the deflection under the failure load. The overbreak around the vault contributed to the reduction of the capacity for cracking and failure by the percentage greater than the reduced effective depth. Of several rock block types considered in this research, the triangular block was the most critical, and the right triangular block under eccentric load was secondly critical for the stability of the tunnel lining system. The dimensionless support reaction curves were derived from the experimental results for single and double lining. The general equation to compute the designed flexural moment was modified.

• Applied Biological Chemistry
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• 제2권
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• pp.9-14
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• 1961

The formation of sulfide from sulfate has been discussed from the thermodynamic principles. No mechanism of the reaction has been presented. From the stoichiometric and Nernst equations for the conversion of sulfate into sulfide, it was concluded that the formation of sulfide from sulfate can take place more readily if pH of a medium is low. The difficulty of this conversion increases with increasing pH. As pH of a medium increases, the degree of dissociation of H₂S into S= increases and this, in turn, renders the chance of precipitation of sulfide as FeS easier. Higher the pH of a soil or medium, greater is the S= concentration. The concentration of ferrous ion required to remove dissolved sulfide in a medium by forming insoluble FeS decreases with increasing pH. From the theory it was pointed out that an application of lime and iron rich foreign substances to a soil may be effective in causing the removal of dissolved sulfide from solution.

• Journal of Chest Surgery
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• 제18권2호
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• pp.232-240
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• 1985

Preoperative and postoperative psychiatric evaluation were done for 51 patients who were undergoing open-heart surgery. The incidence of postoperative psychopathological complications following open-heart surgery was 27.5%. This rate is comparable to that of previous studies. Neurotic reactions occurred in eight patients, delirium in five, and acute psychotic reaction in one. Of those variables which were previously suggested to influence the high incidence, the demographic factors and the severity of preoperative illness were correlated with postoperative psychopathologic dysfunctions. No somatic variable associated with intraoperative or postoperative procedures has been proven to correlate. By preoperative psychiatric evaluations, the patients could be divided into three groups: the Anxiety group, the Denial group, and the Adjusted group. The most important psychological finding was that in patients who demonstrated a high degree of preoperative anxiety or who could not express preoperative anxiety, postoperative psychological complications developed more frequently. With these findings, the preoperative psychiatric interview was recommended for prevention and reduction of postoperative psychiatric complications.

• 대한음성학회지:말소리
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• 제33_34호
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• pp.1-10
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• 1997

Korean stop consonants are well known for their tripple distinction. In word initial position lax, tense and aspirated consonants are all voiceless. They are differentiated by the degree of tension, aspiration and VOT(voice onset time). But in intervocalic position, lax consonants become voiced. In this study I compare the acoustic features of Korean intervocalic lax and tense stops. The closure duration of lax stops is shorter than that of tense consonants. The preceding vowel length is longer in tan than that in tense consonants. I modify the above acoustic characteristics by an experimental methods. For example, I shorten the closure duration of intervocalic tense stops by 5 steps. r also do auditory tests which will show us listener's reaction on the above examples. And do the same job with the preceding vowels. According to the auditory test, the closure duration does an important role in differentiating Korean intervocalic lax and tense stops. But the preceding vowel length has almost nothing to do with the distinction between lax and tense stops. So I conclude that acoustic features also have hierarchy. Some features have categorical characteristics and others don't.

• 소음진동
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• 제7권3호
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• pp.387-392
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• 1997

This paper concerns a SCARA robot with the flexible forearm linked to the rigid upper arm. The equations of motion are derived by the Lagrangian mechanics. For controller design, the perturbation approach is taken to separate the original equations of motion into linear equations describing small perturbed motions and nonlinear equations describing purely rigid motion of the robot. To effect the desired payload motion, open loop control inputs are determined based on the inverse dynamics of the latter. In order to reduce the positional error during maneuver, an active vibration suppression is done. To this end, a feedback control is designed for robustness against disturbance on the basis of the linear equations and the LQR theory modified to have a prescribed degree of stability. The proposed control scheme shows satisfactory performances in experiments as well as in numerical simulations.

• 대한의용생체공학회:의공학회지
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• 제28권3호
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• pp.392-396
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• 2007

In this paper, we develop a new system to visualize the blood flow map in skin tissue, using the technique of Laser Speckle Flowgraphy (LSFG). The measuring unit consists of the laser diode, imaging system, line sensor, scanning mirror, and one-board microcomputer. The speckle signal is analyzed and sent to a PC, where the blood flow in a tissue area of $14mm{\times}26 mm$ is evaluated and displayed in a 2-D color map. It is demonstrated that the new LSFG instrument is useful to evaluate the degree of allergic reaction in patch test.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.187-196
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• 1995

In order to produce fuctional chitooligosaccharides, a strain excreting mainly endo-type chitinase suitable for chitooligosaccharides production was newly screened and identified as Aspergillus fumigatus JC-19. The chitinase excretion was repressed in nutrient rich medium but stimulated by colloidal chitin indicating that the chitinase is inducible type enzyme. Maximum secretion of the enzyme was observed at pH 7.0 and 37$\circ$C . The growth and chitinase production patterns of Aspergillus fumigatus JC-19 showed that the cell growth reached maximum after 4-5 days with final chitinase concentration of 0.46 unit per ml. Excreted chitinase was purified by ammonium sulfate precipitation, colloidal chitin adsorption, anion exchange chromatography, and gel filtration, respectively, and measured M.W of 50 KDa. The enzyme reaction carried out both by crude and purified chitinase showed that the purified chitinase accumulated more chitooligosaccharides of 1-6 degree of polymerization than that of crude chitinase.