• Journal of Microbiology and Biotechnology
• /
• 제21권9호
• /
• pp.979-987
• /
• 2011

Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative $Na^+/H^+$ antiporter (sha) genes in S. coelicolor have been investigated in this study to elucidate the association of the sha on pH variation and secondary metabolism. Through the transcriptional analysis and overexpression experiments on 8 sha genes, we observed that most of the sha expressions were promoted by pH shock, and in the opposite way the pH changes and actinorhodin production were enhanced by the overexpression of each sha. We also confirmed that sha8 especially has a main role in maintaining cell viability and pH homeostasis through $Na^+$ extrusion, in salt effect experiment under the alkaline medium condition by deleting sha8. Moreover, this gene was observed to have a function of pH recovery after pH variation such as the pH shock, being able to cause the sporulation. However, actinorhodin production was not induced by the only pH recovery. The sha8 gene could confer on the host cell the ability to recover pH to the neutral level after pH variation like a pH drop. Sporulation was closely associated with this pH recovery caused by the action of sha8, whereas actinorhodin production was not due to such pH variation patterns alone.

• KSBB Journal
• /
• 제4권2호
• /
• pp.65-68
• /
• 1989

누에 번데기의 단백질 추출 조건을 규명하고자 온도, ph및 시간 변화에 따라 추출된 단백질의 총 질소함량을 Kjeldahl법과 원소 분석기를 이용한 결과는 다음과 같다. 1. 누에 번데기의 초단백질 : 23.34%, 조지방 : 15.61%이나, 2. 온도 변화에 따른 ph 4에서 1시간 추출시 6$0^{\circ}C$:6.76%, 8$0^{\circ}C$:7.94%, 10$0^{\circ}C$:8.67%이고 C.H.N corder의 분석결과는 6$0^{\circ}C$:8.08%, 8$0^{\circ}C$:9.52%, 10$0^{\circ}C$:9.72%로서 두 가지 방법에서 수치는 다르지만 온도 상승에 따라 수용성 질소계수가 증가하는 경향임을 알 수 있다. 3. pH변화에 따른 8$0^{\circ}C$에서 1시간 추출시 pH 4:7.94%, pH 6:8.96%, pH : 8:9.70%, pH : 10:10.67%, pH : 12:10.98%로 온도 상승과 같이 pH증가에 따라 증가하는 경향을 보이고 있다. 4.추출시간의 변화에 따른 10$0^{\circ}C$에서 pH 4인경우 1시간:8.67%, 2시간:9.23%, 3시간:9.76%이고, C.H.N. corder의 결과는 1시간:9.72%, 2시간:10.06%, 3시간:10.83%로서 추출 시간이 늘어남에 따라 증가되는 경향을 보이고 있다.

• 원예과학기술지
• /
• 제33권6호
• /
• pp.854-859
• /
• 2015

본 시험은 배양액 내 pH 변화에 따른 이온과 EC의 모형을 구명하고자 수행하였다. 배양액 내 $HPO_4{^{-2}}$와 $H_2PO_4{^-}$의 변량에 따른 pH가 변하는데, pH 4.0-5.0은 EC의 변량이 상승하고, pH 5.0-7.0은 EC의 변량이 완만하고, pH 7.0-8.0은 다시 상승하였다. 배양액 내 다량원소의 변량을 보면, pH가 상승할수록 K, Ca, N, P의 이온 농도도 증가하는데, 특히 K과 P의 변량이 크게 나타났다. 반면 Mg와 S의 변량은 일정하게 유지되었다. 배양액의 IBM(ion balance model)에 따른 분석에서, EC의 변량은 크게 변하지 않고, 이온의 균형점이 a분면에서 d분면으로 이동하면 pH가 상승하면서 음이온 보다 양이온이 증가하는 것으로 나타났다. 또한 pH 변량이 높을수록 EC 중앙선으로부터 멀어져 배양액의 이온 불균형이 증가되었다. $HPO_4{^{-2}}$와 $H_2PO_4{^-}$의 변량에 대한 K와 Ca의 당량비 보정은 pH가 증가할수록 K는 감소하지만 Ca는 증가하였고, EC 변량의 영향보다 큰 것으로 나타났다. K와 Ca의 당량비 보정에 따른 pH 변량은 0.97의 이차 다항식 상관모형을 나타냈다. 본 연구를 통해 인산염의 구배에 따른 pH, 이온, EC의 변량에 대하여 pH 변량 모형이 구명되었다.

• Journal of Biosystems Engineering
• /
• 제25권3호
• /
• pp.241-250
• /
• 2000

The feasibility of precision fertilizing for small size fields was studied by determining fertilizing amount of nitrogenous and calcareous to a cite specific region. A detailed soil survey at three experimental fields of $672m^2$, $300m^2$ and $140m^2$ revealed a considerable spatial variation of the pH and organic matter(OM) levels. Soil organic matter was measured using Walkley-Black method and soil pH was measured with a pH sensor. Soil sample was obtained by Grid Node Sampling Method. The soil sampling depth was 10∼20 cm from the soil surface. To display soil nutrient variation, a soil map was made using Geographic Information System (GIS) software. In soil mapping, soil data between nodes was interpolated using Inverse Distance Weighting (IDW) method. The variation was about 1∼1.8 in pH value and 1.4∼7% in OM content. Fertilizing Amount of nitrogenous and calcareous was determined by th fertilizing equation which was proposed by National Institute of Agricultural Science and Technology(NIAST). The variation of fertilizing amount was about 3∼11 kg/10a in nitrogenous and 70∼140 kg/10a in calcareous. The results showed a feasibility of precision fertilizing for small size fields.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 봄 학술발표회 논문집
• /
• pp.585-590
• /
• 2001

Physicochemical phenomena in soils are dependent upon pH when using electrokinetic extraction for the contaminants removal especially for heavy metals. pH variation in soils is affected on H$\^$+/ and OH￣ ions produced by electrolysis reaction and buffer capacity of soil. High amount of heavy metals are retained in the soils if the soil buffer capacity remains high enough to resist a change in pH. Therefore, accurate pH estimation of soil is important in the application of electrokinetic mechanism for decontamination and understanding of subsurface physicochemical characteristics is also required as well as considering buffer capacity for the enhanced methods application. For these, buffer capacity and pH distribution were measured for the four soils, and also compared with modeling results. The results of buffer modeling were good agreement with experimental data. It is showed that four soils were effected by buffer capacity

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
• /
• pp.236-245
• /
• 2000

The feasibility of precision farming for small sized fields was studied by determining fertilizing amount of nitrogenous and calcareous to a cite specific region. A detailed soil survey at three experimental fields of 672㎡, 300㎡ and 140㎡ revealed a considerable spatial variation of the pH and organic matter(OM) levels. Soil organic matter was measured using Walkley-Black method and soil pH was measured with a pH sensor. Soil sample was obtained by Grid Node Sampling Method. The soil sampling depth was 10 - 20 cm from the soil surface. To display soil nutrient variation, a soil map was made using Geographic Information System (GIS) software. In soil mapping, soil data between nodes was interpolated using Inverse Distance Weighting (IDW) method. The variation was about 1 - 1.8 in pH value and 1.4 -7 % in OM content. Fertilizing Amount of nitrogenous and calcareous was determined by the fertilizing equation which was proposed by National Institute of Agricultural Science and Technology.(NIAST). The variation of fertilizing amount was about 3 - 11 kg/10a in nitrogenous and 70 - 140 kg/10a in calcareous. The results showed a feasibility of precision fertilizing for small size fields.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2007년도 학술대회
• /
• pp.136-141
• /
• 2007

The frequency accuracy and phase alignment is necessary for ensuring the quality of service (QoS) for applications such as voice, real-time video, wireless hand-off, and data over a converged access medium at the telecom network. As telecom networks evolve from circuit to packet switching, proper synchronization algorithm should be meditated for IP networks to achieve performance quality comparable to that of legacy circuit-switched networks. The Time of Packet (ToP) specified in IEEE 1588 is able to synchronize distributed clocks with an accuracy of less than one microsecond in packet networks. But, The ToP can be affected by impairments of a network such as packet delay variation. This paper proposes the efficient method to minimize the expectable delay variation when ToP synchronizes the distributed clocks. The simulation results are presented to demonstrate the improved performance case when the efficient ToP transmit algorithm is applied.

• 한국세라믹학회지
• /
• 제26권2호
• /
• pp.157-166
• /
• 1989

The effect of pH variation in starting solution on the characteristics of hydroxyapatite precipitates and powder prepared by the wet method was investigated. Hydroxyapatite precipitates was agglomerated, the average agglomerated particle size was decreased in the range from 2 to 6${\mu}{\textrm}{m}$ with increasing pH values in starting solution. The aspect ratio of rod-shaped hydroxyapatite particle was rapidly increased at pH 11 and 11.5. The maximum specific surface area, 91.1$m^2$/g, was at pH 10.5. Dried powder prepared at high pH values contained more minutes CO2 than that prepared at low pH values. The poor crystallinity was maintained up to $600^{\circ}C$ regardless of the pH values in starting solutions. However, the second phase or high crsytalline hydroxypatite phase appeared above 80$0^{\circ}C$. In pH 9.5 and pH 10, $\beta$-whitlockite transformed to $\alpha$-whitlockite at 120$0^{\circ}C$, while in pH 10.5-11.5, hydroxyapatite phase was maintained up to 120$0^{\circ}C$.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 추계학술대회
• /
• pp.140-144
• /
• 2000

In treatment of contaminated ground by electrokinetic remediation, pH control is the main prolllem for enhancinfi remediation efficiency. In this study, analysed pH variation characteristics according to contaminant(Pb$^{2+}$) concentration and estimated remediation efficiency with organic acid to prevent precipitation in cathode due to hydroxide ion occurrence. Because most of transported Pb$^{2+}$ is precipitatecl according as pH is increased at specimen adjacent to cathode reservoir, little magnitude of Pb$^{2+}$ is flowed out of specimen.cimen.

• 한국환경보건학회지
• /
• 제20권2호
• /
• pp.14-21
• /
• 1994

This study was carried out to find out the elution characteristics of 4 kinds of sludges and a dust by the variation of pH. Four kinds of sludges were obtained from the Industrial wastes, and the dust, from the iron-and-steel waste. These samples were analyzed by "Official Method for Waste", and the results were summarized as follows. 1. The amounts of heavy metals The concentrations of Cu were 1,940