• 한국미생물·생명공학회지
• /
• 제20권5호
• /
• pp.597-606
• /
• 1992

Alcaligenes eutrophus 균주로 poly-Beta-hydroxybutyrate(PHB) 생산을 위한 연속배양 공정의 성능에 미치는 희석비율, 주입 포도당 및 염화암모늄농도의 영향에 대하여 연구하였다. 주입 기질농도가 일정할때( 주입 포도당농도=20g/l, 주입 염화암모늄농도=2g/l), 생체성장속도와 PHB생성속도는 희석비율이 각각 0.1, $0.06h^{-1}$에서 최고 값을 나타냈고, $0.13h^{-1}$에서 세포가 전부 배출되었다. 희석비율이 증가함에 따라 비PHB 생성속도는 계속 증가하였지만 PHB 축적비는 50%에서 25%로 감소하였다. 세포농도는 주입 염화암모늄농도가 2g/l일 때 최고값을 나타내었고, 그 이상의 농도에서는 감소하였다. 이 실험결과로 암모늄에 의한 기질저해가 있음을 알 수 있었다. 주입 포도당농도가 30g/l에서 세포농도는 최고값을 나타냈지만 PHB 농도는 계속 증가하였따. 모델속도식에 대한 매개변수는 도식적 방법과 매개변수 추정으로 구하였고 희석비율, 주입 포도당농도, 주입 염화암모늄농도의영향에 대하여 모사한 결과 실험데이타와 잘 일치하였다.

• 자원환경지질
• /
• 제29권3호
• /
• pp.335-343
• /
• 1996

The dipole-dipol electrical resistivity survey was conducted to investigate the probable contamination of the Han river by leachate from the near-by Nanjido Landfill. The survey line of 3 km was set along the unpaved road toward the Han river. For the convenience of the field work, the survey line was divided into four segments. The complete two-dimensional resistivity section was constructed by connecting the inversion result of each segment. Gravity survey was also carried out along the profile parallel to the resistivity line. Near surface resistivity generally appeared to be of very low value in most part of the survey area and the boundary between the alluvium layer and underlying basement rocks is well discriminated on the resistivity section. These results agree well with those of the preceding Schlumberger depth sounding made at adjacent area by Lee and fun (1995). The variation of thickness of the alluvium layer delineated by gravity anomaly profile also correlates well with the result of the resistivity survey on the qualitative basis. The problem of contamination by leachate from the Nanjido Landfill, where various waste materials have been dumped without any proper treatment facilities, has been remains unsolved yet. Therefore, we present the most probable passages of leachate flow based on the survey results and have briefly discussed about measure for contamination control. Considering the thickness of alluvium and the possible existence of fractured zone, the middle point between 1st and 2nd landfill and the midst of 1st landfill are the most hazardous regions to make leachates flow into the Han river. Since large amounts of leachates are observed from the test wells located on the lines extending from the border between the 1st and 2nd landfill and the middle of the lst landfill, contamination protection barriers are strongly recommended near these regions.

• 보건행정학회지
• /
• 제18권2호
• /
• pp.86-106
• /
• 2008

This research analyzed. knowledge structure and its effect factor by analysis of co-author and keyword network in Korea's health policy and administration sector. The data was extracted from 339 articles listed in the Korean Journal of Health Policy and Administration, and was transformed into a co-author and keyword matrix. In this matrix the existence of a link was defined by impact factors which were calculated by the weight value of what the role was and the rate of how many authors contributed. We demonstrated that the research achievement was dependent on the author's status and network index. Analysis methods were neighborhood degree, correspondence analysis, multiple regression and the difference of weight distribution by research fields. Co-author networks were developed as closeness centrality as well as degree centrality by a few high productivity researchers. In particular, power law distribution was discovered in impact factor and research productivity. The effect of the author's role was significant in both the impact factor calculated by the participatory rate and the number of listed articles. Especially, this journal shared its major researchers who had a licensed physician with the Journal of Preventive Medicine and Public Health. Therefore, social scientists were likely to be small co-author network differently from natural scientists. It was so called 'two cultures' phenomenon. This study showed how can we verified academic research structure existed in the unit of journal like as citation networks. The co-author networks in the field of health policy and administration had more differentiated and clustered than preventive medicine and epidemiology fields.

• 한국지반환경공학회 논문집
• /
• 제7권6호
• /
• pp.5-12
• /
• 2006

본 연구는 struvite 결정화 적용시 $Mg^{2+}$과 $PO_4{^{3-}}$의 주입량, pH, 반응시간 그리고 결정핵 주입과 같은 실험인자가 혐기성 발효액의 질소 및 인 제거에 미치는 영향을 실험적으로 검토하였다. $Mg^{2+}:NH_4{^+}:PO_4{^{3-}}$의 적정 주입 몰비는 1.2:1.0:1.2 였다. 최적 주입 몰비에서 $NH_4{^+}-N$와 $PO_4{^{3-}}-P$의 평균제거율 및 반응속도상수는 각각 79.2, 96.8%, 0.157 그리고 $0.344min^{-1}$였다. 최적 pH는 11이었으며 반응시간 10분 이내에 충분히 struvite 결정화가 이루어 졌다. 결정핵 주입 유 무에서 결정핵 주입량 1g/L에서 가장 낮은 영양염류 잔류농도 값을 보여주었으며, SEM 사진 분석 결과 결정핵의 성장을 관찰할 수 있었다. 또한 struvite 침전물의 XRD 분석 결과 사방정계 결정구조를 가지는 것으로 확인되었다.

• 한국농공학회지
• /
• 제30권4호
• /
• pp.134-153
• /
• 1988

This paper was carried out to investigate the existence of a unique stress- strain behavior by obtaining some factors influencing the time dependent stress- strain behavior of clay. The results obtained from this study were summarized as follows ; 1. The relationship between stress ratro and strain in normally consolidated clay was in- dependent on pre-shear consolidation pressure. Therefore, shear strain could be expressed as a function with stress ratio. 2. The constitutive equation of shear strain on Modified Carn Clay Model coincided better with the observed value than Cam Clay Model. 3. The relationships between deviator stress and shear strain, between pore water pressure and shear strain were unified by the mean equivalent pressure. 4. The shear strain contour in norrnally consolidated clay was increased linearly through origin, but that in overconsolidated clay was not in accordance with the result of the former. 5. Because the effective stress path of normally consolidated clay was unified by the mean equivalent pressure, state boundary surface in (e,p,q) space was transformed into two dimensional surface. But it was considered to be suitable that the unified stress- strain in overconsolidated clay be expressed by a function with overconsolidation ratio. 6. The deviator for constant strain was increased linearly with increment of strain rate ($\varepsilon$) on semi-log scale, but pore water pressure was decreased. 7. The behavior of stress relaxation was transformed from linear to curvilinear with inc - rement of strain rate before stress relaxation test, and pore water pressure was increased in total range. 8. The strain of creep was increased linearly with increment of time on semi-log scale. The greater the strain rate before creep test became, the greater the increment of strain of creep became. And the pore water pressure during creep test was increased generally with increment of time on semi-log scale.

• Archives of Pharmacal Research
• /
• 제22권5호
• /
• pp.464-473
• /
• 1999

Regulation of phosphcholine-hydrolyzing phosphatase (phosphocholine-phosphatase) activity, purified from bovine brain, was examined under physiological conditions. Various endogenous phosphomonoesters, which were utilized as substrate, inhibited the phosphocoline-phosphatase activity competitively (Ki 5.5-$82.0 {\mu}M$); among phosphomonoesters tested, there was a similar order of capability between the binding affinity of substrate and the inhibitory potency. In addition, phosphate ions also inhibited the phosphatase activity competitively with a Ki value of approximately $16{\mu}M$. Although leucine or theophylline inhibited the phosphatase activity at pH 9.0, their inhibitory action decreased greatly at pH 7.4. The pH-Km and pH-Vm profiles indicate that ionizable amino acids are involved in substrate binding as well as catalysis, alluding that the phosphatase activity may be highly dependent on the intracellular pH. Amino acid modification study supports the existence of tyrosine, arginine or lysine residue in the active site, and the participation of tyrosine residue in the catalytic action may e suggested positively for the susceptibility to the action of tetranitromethane or HOl-generator. Separately, the oxidative inactivation of phosphocholine-phosphatase activity was investigated. Of oxidants tested, HOONO, HOCl, HOl and $ascorbate/Cu^{2+}$ system were effective to inactivate the phosphatase activity. Noteworthy, a remarkable inativation was accomplished by $30{\mu}M$ HOCl in combination with 1 mM Kl. Inaddition, $Cu^{2+}(3{\mu}M) $in combination with ascorbate at concentrations as low as 0.1-0.3 mM reduced the phosphatase activity to a great extent. From these results, it is proposed that the phosphocholine-phosphatase activity may be regulated endogenously and susceptible to the various oxidant system in vivo.

• 대한수의학회지
• /
• 제40권2호
• /
• pp.325-332
• /
• 2000

The growth characteristics and the cellular protein patterns of the Lactobacillus plantarum isolated and identified from oat silage were examined in order to confirm whether it will be used practically as probiotics or not. L plantarum was identified by morphological and biochemical tests including of final conforming by API 50CHL kit. The cultivation in MRS broth of the strain under the condition of different temperature, proved that they grew into $2.0{\times}10^{9}$ in $25^{\circ}C$, into $1.4{\times}10^{9}$ in $35^{\circ}C$ but they decreased into $4.5{\times}10^{5}$ growth in $45^{\circ}C$. The comparison of the growth by measurement of O.D600nm value after 24 hour cultivation between L plantarum and commercial probiotics, showed that the strain had a higher growth than commercial as 1.841 : 1.623. The measurement of it under bile acid's existence, indicated that this isolation was not influenced by bile acid and the tolerance was $3.2{\times}10^{9}$, $3.9{\times}10^{9}$ and $3.2{\times}10^{9}$, respectively, when each of 0%, 1%, and 2% oxigall existed. The examination of their antibiotics susceptibility by disk diffusion test, proved that L plantarum showed resistance against danofloxacin(5mcg), gentamycin(10mcg), kanamycin(30mcg), neomycin(30mcg) and streptomycin(10mcg). Based upon the test of the bacteriocin formation of this L plantarum, it was found out that the inhibition zone was not formed. In growth of L plantarum and E coli in nutrient broth, all E coli died out within 6 hours after cultures.

• 조형예술학연구
• /
• 제13권1호
• /
• pp.39-60
• /
• 2008

Nature/Landscape is surrounding space in which we make living. It is considerably comprehensive tenn. but on the other hand, the site can be existence, experience, and certain circumstance with boundaries. Based on these places, through contemporary art criticism, this study is to contemplate how art since 1960s, especially, site-specific art in three-dimensional space intervene in the environment. Artists of today put more value on the process and act of art making founded on the external, and they tend to create the characteristic of site or to indicate linguistic documentation. Moreover, a large-scale tendency of contemporary sculpture and 'occupation of specific site' seems to accede spatial conception from architecture. The core that recognizes these artworks is with body, that is to say, the space in which Self becomes the subject by changing the structure of the work while moving around it. In particular, 'Site-specific Art (in situ)' sometimes determines the form inward or outward It also relates directly on viewer's five senses by looking, hearing, and feeling, touching, and interacting. For example, in Richard Serra's , the viewer who moves around the work has the role to manipulate the movement of the work by perception. Works of In situ and works that planned for specific site suggest 'occupation of site' as of the function of the work These sites are ideal and special as well as being independent. Ultimately, it seems that the creative process of contemporary artists is to carry those intended form on the structure of perception. Furthermore, law of nature such as entropy, and acceptance of contingency helped organic structure of artwork become more abundant. For Robert Smithson, entropy suggests of reaching to a state of equilibriumin which everything is the same. This means that any core is justifiable and any rank is possible. Because the world without a core is a labyrinth of boundless exploration.