• Clean Technology
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• v.28 no.2
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• pp.147-154
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• 2022

Titanate nanotubes (TNTs) were synthesized via alkaline hydrothermal treatment using commercial TiO₂ nanoparticles (P25). The TNTs were prepared at various TiO₂/NaOH ratios, hydrothermal temperatures, and hydrothermal times. The synthesized catalysts were characterized by X-ray diffraction, field-emission scanning electron microscopy, N₂ adsorption-desorption isotherms, field-emission transmission electron microscopy, and ultraviolet-visible spectroscopy. TNTs were generated upon a decrease in the TiO₂/NaOH ratio due to the dissolution of TiO₂ in the alkaline solution and the generation of new Ti-O-Ti bonds to form titanate nanoplates and nanotubes. The hydrothermal treatment temperature and time were important factors for promoting the nucleation and growth of TNTs. The TNT catalyst with the largest surface area (389.32 m² g^-1) was obtained with a TiO₂/NaOH ratio of 0.25, a hydrothermal treatment temperature of 130 ℃, and a hydrothermal treatment time of 36 h. Additionally, we investigated the photocatalytic activity of methyl violet 2B (MV) over the TNT catalysts under UV irradiation and found that the degradation efficiencies of the TNTs were higher than that of P25. Among the TNT catalysts, the TNT catalyst that was hydrothermally synthesized for 36 h (TNT 36 h) exhibited a 96.9% degradation efficiency and a degradation rate constant that was 4.8 times higher than P25 due to its large surface area, which allowed for more contact between the MV molecules and TNT surfaces and facilitated rapid electron transfer. Finally, these results were correlated with the specific surface area.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.61-73
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• 2009

Many software reliability growth models(SRGM) have been proposed since the software reliability issue was raised in 1972. The technology to estimate and grow the reliability of developing S/W to target value during testing phase were developed using them. Most of these propositions assumed the S/W debugging testing efforts be constant or even did not consider them. A few papers were presented as the software reliability evaluation considering the testing effort was important afterwards. The testing effort forms which have been presented by this kind of papers were exponential, Rayleigh, Weibull, or Logistic functions, and one of these 4 types was used as a testing effort function depending on the S/W developing circumstances. I propose the methology to evaluate the SRGM using least square estimater and maximum likelihood estimater for those 4 functions, and then examine parameters applying actual data adopted from real field test of developing S/W.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.69-78
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• 2024

We have proposed a method for estimating the size-dependent mortality (M) of short-lived semelparous cephalopod species. To estimate the size-dependent mortality of a winter cohort of the common squid Todarodes pacificus, a commercially important cephalopod species in the North Pacific, we used the data and results of previous studies. On the basis of the bigger-is-better the steady-state hypothesis, we derived a theoretical mortality curve by assuming M as an inverse function of mantle length (ML). The derived constant for size-specific instantaneous mortality (q), assuming an embryonic survival rate of 86.6%, was 0.413 day^-1 mm in ML. Estimates of life-stage-specific M ranged from 0.0280 to 0.435 day^-1 for paralarvae, 0.00278 to 0.0269 day^-1 for juveniles, 0.00197 to 0.00275 day^-1 for pre-spawning adults, and 0.0913 to 0.0920 day^-1 for post-spawning adults. Sensitivity analyses showed that the derived size-dependent M did not significantly change with varying embryonic survival rates, from 48%, the lowest reported value, to 100%. Additionally, comparison of the length frequencies derived from our simulations with those derived from catch data did not show a significant difference, suggesting that our approach and procedures are reliable for stock assessment and management of the common squid.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.135-140
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• 1995

Changes in pH of the soaking solution and physical properties of the soybean curd during immersing in solution of different concentrations at different temperatures were determined. Compared with $0{\sim}3%$ NaCl soaking solution, 5% NaCl soaking solution distinctively reduced the pH drop, increasing rate of turbidity and microorganism growth during storage. This indicated the concentration of soaking solution influences the shelf life of curd. As the storage temperature was lowered to $5^{\circ}C$, their changing rates were also reduced. Physical properties such as initial stress $({\sigma}_0)$, elastic constant (E), viscous constant $({\eta})$ and failure test were influenced by storage temperature, but not a function of concentration of salt solution. The result of the sensory test indicated the hardness and salty taste of curd were statistically significant among samples and $1{\sim}5%$ NaCl solutions did not show any significant difference in the salty taste.

• FLOWER RESEARCH JOURNAL
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• v.16 no.2
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• pp.112-117
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• 2008

Plug seedlings of vinca (Catharanthus roseus L. 'Pacifica Punch') and salvia (Salvia splendens F. Sellow ex Roem & Schult 'Maestro') were transplanted into square plastic pots (145 mL volume) filled with a soilless growing medium. To determine the effect of application rate on the growing medium EC and growth of plants, 0, 0.5, 1.0, 1.5, 2.0 and 4.0 g per pot of a controlled release fertilizer (14-14-14 Osmocote, 14N-6.2P-11.6K) were mixed with the growing medium. Plants were subirrigated daily with tap water. In both vinca and salvia, growing medium EC increased as application rate was elevated. Growing medium EC was relatively constant over a whole crop period when the application rate was less than 1.5 g per pot, while it decreased throughout the experiment at higher application rates such as 2.0 to 4.0g per pot in both species. The greatest leaf area, plant height, and shoot dry weight of vinca were obtained when plants were fertilized with 2.0 to 4.0 g per pot of the fertilizer, resulting in a growing medium EC of $1.0{\sim}1.7dS{\cdot}m^{-1}$ throughout the experiment. Leaf area, shoot dry weight, and chlorophyll content of salvia increased with elevated application rates. Leaf area, shoot dry weight, and chlorophyll content of salvia were the greatest when plants were fertilized with 4.0 g per pot, resulting in growing medium EC of $1.0{\sim}4.0dS{\cdot}m^{-1}$ throughout the experiment. Plant height of salvia was the greatest when plants were fertilized with 2.0 to 4.0g per pot. Concentrations of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and sulfur (S) in the shoots of vinca increased, while concentration of calcium (Ca) decreased with elevated application rates. Concentrations of boron (B) and manganese (Mn) in the shoots of vinca increased as the application rate decreased.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4279-4295
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• 1977

Two types of model were established in order to product the soil moisture content by which information on irrigation could be obtained. Model-I was to represent the soil moisture depletion and was established based on the concept of water balance in a given soil profile. Model-II was a mathematical model derived from the analysis of soil moisture variation curves which were drawn from the observed data. In establishing the Model-I, the method and procedure to estimate parameters for the determination of the variables such as evapotranspirations, effective rainfalls, and drainage amounts were discussed. Empirical equations representing soil moisture variation curves were derived from the observed data as the Model-II. The procedure for forecasting timing and amounts of irrigation under the given soil moisture content was discussed. The established models were checked by comparing the observed data with those predicted by the model. Obtained results are summarized as follows: 1. As a water balance model of a given soil profile, the soil moisture depletion D, could be represented as the equation(2). 2. Among the various empirical formulae for potential evapotranspiration (Etp), Penman's formula was best fit to the data observed with the evaporation pans and tanks in Suweon area. High degree of positive correlation between Penman's predicted data and observed data with a large evaporation pan was confirmed. and the regression enquation was Y=0.7436X+17.2918, where Y represents evaporation rate from large evaporation pan, in mm/10days, and X represents potential evapotranspiration rate estimated by use of Penman's formula. 3. Evapotranspiration, Et, could be estimated from the potential evapotranspiration, Etp, by introducing the consumptive use coefficient, Kc, which was repre sensed by the following relationship: Kc=Kco$.$Ka＋Ks‥‥‥(Eq. 6) where Kco : crop coefficient Ka : coefficient depending on the soil moisture content Ks : correction coefficient a. Crop coefficient. Kco. Crop coefficients of barley, bean, and wheat for each growth stage were found to be dependent on the crop. b. Coefficient depending on the soil moisture content, Ka. The values of Ka for clay loam, sandy loam, and loamy sand revealed a similar tendency to those of Pierce type. c. Correction coefficent, Ks. Following relationships were established to estimate Ks values: Ks=Kc-Kco$.$Ka, where Ks=0 if Kc,=Kco$.$K0$\geq$1.0, otherwise Ks=1-Kco$.$Ka 4. Effective rainfall, Re, was estimated by using following relationships : Re=D, if R-D$\geq$0, otherwise, Re=R 5. The difference between rainfall, R, and the soil moisture depletion D, was taken as drainage amount, Wd. {{{{D= SUM from { {i }=1} to n (Et-Re-I+Wd)}}}} if Wd=0, otherwise, {{{{D= SUM from { {i }=tf} to n (Et-Re-I+Wd)}}}} where tf=2∼3 days. 6. The curves and their corresponding empirical equations for the variation of soil moisture depending on the soil types, soil depths are shown on Fig. 8 (a,b.c,d). The general mathematical model on soil moisture variation depending on seasons, weather, and soil types were as follow: {{{{SMC= SUM ( { C}_{i }Exp( { - lambda }_{i } { t}_{i } )+ { Re}_{i } - { Excess}_{i } )}}}} where SMC : soil moisture content C : constant depending on an initial soil moisture content $\lambda$ : constant depending on season t : time Re : effective rainfall Excess : drainage and excess soil moisture other than drainage. The values of $\lambda$ are shown on Table 1. 7. The timing and amount of irrigation could be predicted by the equation (9-a) and (9-b,c), respectively. 8. Under the given conditions, the model for scheduling irrigation was completed. Fig. 9 show computer flow charts of the model. a. To estimate a potential evapotranspiration, Penman's equation was used if a complete observed meteorological data were available, and Jensen-Haise's equation was used if a forecasted meteorological data were available, However none of the observed or forecasted data were available, the equation (15) was used. b. As an input time data, a crop carlender was used, which was made based on the time when the growth stage of the crop shows it's maximum effective leaf coverage. 9. For the purpose of validation of the models, observed data of soil moiture content under various conditions from May, 1975 to July, 1975 were compared to the data predicted by Model-I and Model-II. Model-I shows the relative error of 4.6 to 14.3 percent which is an acceptable range of error in view of engineering purpose. Model-II shows 3 to 16.7 percent of relative error which is a little larger than the one from the Model-I. 10. Comparing two models, the followings are concluded: Model-I established on the theoretical background can predict with a satisfiable reliability far practical use provided that forecasted meteorological data are available. On the other hand, Model-II was superior to Model-I in it's simplicity, but it needs long period and wide scope of observed data to predict acceptable soil moisture content. Further studies are needed on the Model-II to make it acceptable in practical use.

• Journal of the Mineralogical Society of Korea
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• v.24 no.3
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• pp.235-244
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• 2011

A batch experiment of pyrite oxidation was performed and the surfaces of the reacted pyrite were regularly observed with the scanning electron microscope (SEM) together with the chemical compositions of the solution to help understand the oxidation mechanisms of pyrite by Acidithiobacillus ferrooxidans (Af). The dissolved Fe concentrations clearly indicated that Af experiences the lag and then exponential growth phase. An Af cell was observed to be attached to the surface of pyrite during the lag, implying that a direct leaching by the microbe really happens for the period. It is not certain, however, whether the main mechanism of pyrite oxidation during that time was the direct leaching or not, because there were just a few cells confirmed to be attached and most of the dissolved Fe was Fe(III). The dissolved Fe concentration stayed almost constant from the mid-lag phase to just before the onset of the exponential phase, suggesting that AI needs an adaptation time to switch its oxidation mechanism from one to the other whichever it is during that stage of growth. The moment of Af's cell division was observed by SEM on the surface of pyrite during the lag phase. The corrosion outline around the dividing cell was quite similar to the shape of the cell itself, which implies that the rate of the microbial oxidation is very uneven and the rate when the cell metabolizes should be much faster than that calculated from the concentration variation of the dissolved Fe. The number of etch holes by Af is much higher on the inoculated surfaces, indicating the average rate of pyrite oxidation is also much faster than that of abiotic oxidation. The microbial etch holes on pyrite surface are small and deep, which may influence the transition of the growth phases of Af from lag to exponential.

• KSBB Journal
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• v.24 no.4
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• pp.377-382
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• 2009

The culture condition of growing Chlorella minutissima was optimized to produce biodiesel for fed-batch cultivation. First, under heterotrophic cultivation, the optimum level of glucose was determined to be 10 g/L for 20 days. After, three cultivation conditions were operated: autotrophic, heterotrophic, and mixotrophic growth. The lipid level and the maximum cell concentration from the fed-batch heterotrophic process were 32.0 (%, v/v) and 15.0 (g-dry wt./L) in 20 L flask, respectively. In addition, since the relatively constant specific lipid production rate was observed as 0.040 (% lipid/g-dry wt./day) at the latter period of cultivation time, the fed-batch process could maintain continuous lipid production. Fed-batch process is higher than those values from the batch process. The lipids from the fed-batch process contained over 38% of $C_{18}$, known as the suitable composition for the biodiesel application. For mixotrophic and heterotrophic growth under fed-batch condition, glucose was proved to be an appropriate carbon source for a large scale outdoor cultivation. For fed-batch cultivation, the feeding rate of seawater medium containing glucose was decided to be 0.5 L/day. The mixotrophic cultivation maintained maximum cell concentration of 24 (g-dry wt./L) and the lipid level of 43 (%, w/w). The lipid composition from this process was also proved to be suitable for the biodiesel production. The fatty acids from the mixotrophic growth contains 18% of $C_{17}$ and 49% of $C_{18}$, implying It also tells that C. minutissima is a suitable resource of biodiesel. Especially, the mixotrophic cultivation with fed-batch process might be useful for the large scale cultivation for the biodiesel production.

• Journal of Plant Biology
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• v.35 no.4
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• pp.403-408
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• 1992

The flowering in Lemna gibba G3, a long-day plant, was promoted under continuous light by agmatine, putrescine, spermidine and spermine present in the culture medium. Methylglyoxal-bis (guanylhydrazone) (MGBG) and cyc10hexylamine (CHA), inhibitors of polyamine biosynthesis, were found to suppress the flowering in the plants. The vegetative grov.1h rate was kept constant while the flowering was being promoted by the pOlyamines, and the inhibitors with depressive effect on flowering showed stimulatory effect on vegetative grov.1h. The pattern of vegetative growth during floral promotion or depression was an indication that the promotive action of the pOlyamines and the suppressive effect of the inhibitors may be outcome of their possible involvement specifically in the flowering process rather than in broad spectrum of growth of L. gibba G3. The degree of promotive action of spermdine and spermine could not be altered (or lessened) by simultaneous application of their inhibitors to the medium. This phenomenon indicates that the flowering process in L. gibba G3 may largely be dependent to the status of endogenous spermidine and spermine. Endogenous level of spermidine in florally induced Lemna, was found to rapidly increase. In 24 h of floral induction, the content reached at the level 2 times higher than that in non-induced plants. The elevated level of spermidine provides an additional, though premature, evidence supporting the postulation that endogenous polyamine status might play an important role in the very early stage of floral induction in L. gibba G3.bba G3.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.