• International Journal of Computer Science & Network Security
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• v.24 no.6
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• pp.200-206
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• 2024

Laser induced breakdown spectroscopy (LIBS) technique has been used for the elemental composition of the soils. In this technique, a high energy laser pulse is focused on a sample to produce plasma. From the spectroscopic analysis of such plasma plume, we have determined the different elements present in the soil. This technique is effective and rapid for the qualitative and quantitative analysis of all type of samples. In this work a Q-switched Nd: YAG laser operating with its fundamental mode (1064 nm laser wavelength), 5 nanosecond pulse width, and 10 Hz repetition rate was focused on soil samples using 10 cm quartz lens. The emission spectra of soil consist of Iron (Fe), Calcium (Ca), Titanium (Ti), Silicon (Si), Aluminum (Al), Magnesium (Mg), Manganese (Mn), Potassium (K), Nickel (Ni), Chromium (Cr), Copper (Cu), Mercury (Hg), Barium (Ba), Vanadium (V), Lead (Pb), Nitrogen (N), Scandium (Sc), Hydrogen (H), Strontium (Sr), and Lithium (Li) with different finger-prints of the transition lines. The maximum intensity of the transition lines was observed close to the surface of the sample and it was decreased along the axial direction of the plasma expansion due to the thermalization and the recombination process. We have also determined the plasma parameters such as electron temperature and the electron number density of the plasma using Boltzmann's plot method as well as the Stark broadening of the transition lines respectively. The electron temperature is estimated at 14611 °K, whereas the electron number density i.e. 4.1 × 10¹⁶ cm^-3 lies close to the surface.

• Transactions of Materials Processing
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• v.33 no.3
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• pp.178-184
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• 2024

In this study, we investigated the effects of extrusion ratio and extrusion temperature on the microstructure and tensile properties of extruded Mg-6Al-0.3Mn-0.3Ca-0.2Y (SEN6) alloy. As the extrusion ratio and temperature increase, dynamic recrystallization during extrusion is promoted, leading to the formation of a fully recrystallized microstructure with increased grain size. Additionally, the increases in extrusion ratio and temperature lead to texture strengthening, exhibiting a higher maximum texture intensity. The extruded materials contain three types of secondary phases, i.e., Al₈Mn₄Y, Al₂Y, and Al₂Ca, with irregular or polygonal shapes. The quantity, size, distribution, and area fraction of the second-phase particles are nearly identical between the two materials. Despite its larger grain size, the tensile yield strength of the material extruded at 450 ℃ and an extrusion ratio of 25 (450-25) is higher than that of the material extruded at 325 ℃ and an extrusion ratio of 10 (325-10), which is mainly attributed to the stronger texture hardening effect of the former. The ultimate tensile strength is similar in the two materials, owing to the higher work hardening rate in the 325-10 extrudate. Despite differences in grain size and recrystallization fraction, numerous twins are formed throughout the specimen during tensile deformation in both materials; consequently, the two materials exhibit nearly the same tensile elongation.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.170-174
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• 2024

A laser beam propagating in free space can be negatively affected by atmospheric turbulence. To overcome this and correct the wavefront error of the laser beam itself, a deformable mirror (DM), which is a key component of adaptive optics, is widely used. In this paper, a novel precision assembling method is suggested for a multi-channel high-density DM. The material of the mirror sheet of the DM is silicon carbide (SiC), and the actuator is a stacked-type lead-magnesium-niobate (Pb(Mg_1/3Nb_2/3)O₃; PMN). To connect the mirror sheet and each actuator, a flexure is inserted. The flexure can make the DM operate with full strokes without the failure of adhesive. A series of jigs were designed and applied in order to assemble these three parts (the mirror sheet, actuators, and flexures) precisely. After assembly, the performance of the DM was also checked.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.147-154
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• 1999

This study was carried out to obtain reasonable management method of salt-affected soil for ecological restoration in the reclaimed land. Chemical properties of reclaimed soil was investigated base on reclamation years. Ionic acitivity in soil and satruration extract were analyzed to estimate the effect of salt interception by planting ground treatment. The soil porperties of reclaimed land was saline-sodic soil with $11.3dSm^{-1}$ of electrical conductivity, 34.8% of exchangeable sodium percent in first reclamation year. Electrical conductivity, exchangeable sodium and exchangeable chlorine were remarkedly decreased during six years after reclamation but chemical properties of reclaimed soil was unsuitable status for tree growth. Exchangeable sodium perecnt was higher in the neighborhood parks and street tree sites than in the buffer green spaces and was higher in subsoil than in topsoil of profile in all sites. Content of soduim, chloride and sulfate in saturation extract were more than other ions. Content of soduim and chloride were higher in the neighborhood parks and street tree sites than in the buffer green spaces and were higher in subsoil than in topsoil. Content of calcium plus magnesium of soil was higher in the buffer green space than in the neighborhood park and street tree but content of calcium and magnesium in saturation extract were higher, as result from exchangeable sodium, in the neighborhood parks and street tree sites than in the buffer green spaces. Concentration of salt in soil showed the difference with mounding height and planting ground treatment. The lowest concentration of salt appeared in buffer green spaces and street tree sites was the highest. Salt interception by mounding height in the same planting ground treatment was more effective 120cm of mounding height than 70cm of mounding height.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.140-146
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• 2010

Monitoring of the dynamic changes at paddy rice agriculture is very important for agricultural sustainability. Field monitoring was performed to evaluate the soil chemical properties of 260 paddy soil samples every four years from 1999 to 2007 in Gyeongnam Province. Soil chemical properties such as pH, organic matter, available phosphate, silicate, exchangeable potassium, calcium, and magnesium contents were analyzed. The contents of exchangeable cations, and available silicate were significantly increased in 2007 compared to 1999. The chemical contents of organic matter, exchangeable potassium, and magnesium were significantly increased in acid sulfate soil, and silty clay loam compared to those of other soil types, and textures. Especially, content of organic matter was significantly increased in hill area compared to other soil topographies, while exchangeable potassium was significantly decreased. Principle component analysis (PCA) of chemical properties in paddy soils was obtained with eigenvalues > 1 summing 39.1%of variance for PC1, 20.4%of variance for PC2, and 59.5%of the total variance in the all of soil chemical properties. Therefore, principal component analysis is more effective for monitoring from chemical properties of paddy soil.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.400-409
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• 2015

This study examined the plant growth and development characteristics of leafy vegetables on the hydroponic substrates of waste wood chips, radiate pine chips, and mat type of waste wood chips. The bulk density of waste wood chips and radiata pine chips were $0.2g/cm^3$ and $0.16g/cm^3$, respectively. The moisture retention properties of both the radiata pine chips and waste wood chips were found to be similar but not better than those of the control rock wool and coco peat hydroponic substrates. The moisture retention property of the mat type was found to be the lowest. The chemical analysis of waste wood hydroponic substrates (w/v) was as follows.; The pH was 6.59, electric conductivity was 6.76 dS/m, total nitrogen content was 0.5%, C/N ratio was 113%, phosphorus was 10.1 ppm, potassium was 77 ppm, calcium was 531 ppm, magnesium was 49 ppm, and sodium was 96 ppm. The results from the radiata pine chemical analysis showed that it had a pH of 5.29, electric conductivity of 4.49 dS/m, total nitrogen content of 0.32%, C/N ratio of 180%, phosphorus of 6.4 ppm, potassium of 83 ppm, calcium of 97 ppm, magnesium of 29 ppm, and sodium of 59 ppm. Except for the plants grown in mat type, the developmental characteristics of the plants grown in rock wool and coco peat hydroponic substrates were similar. Based on the results of the experiment, waste wood resources may possibly be used as an organic solid medium in place of the existing rock wool and coco peat medium.

• Journal of Life Science
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• v.22 no.5
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• pp.575-581
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• 2012

This study was conducted to develop an economical optimum medium composition for the mass production of $Lactobacillus$ $plantarum$ and $Lactobacillus$ $reuteri$, livestock probiotics. Medium ingredient factors were selected on the basis of MRS broth composition, and the 15 ingredient variables were as follows: sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, dipotassium phosphate, manganese chloride, magnesium chloride, tween 80, sodium chloride, sodium acetate, ammonium citrate, sodium sulphate, and ferrous sulphate. The Plackett Burman design, consisting of 20 runs, was employed for the analysis of ingredient effects on cell growth of $L.$ $plantarum$ and $L.$ $reuteri$. As a result, sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, sodium acetate, and ammonium citrate positively influenced the growth of $L.$ $plantarum$. Additionally, yeast extract, soy peptone, $K_2PHO_4$, and tween 80 positively influenced the growth of $L.$ $reuteri$. Positive effects were found from sucrose, yeast extract, and soy peptone in the integrated analysis of the effects of both $L.$ $plantarum$ and $L.$ $reuteri$. Finally, effective medium components for both strains were found as follows: sucrose (20.0 g/l), glucose (5.0 g/l), soy peptone (11.0 g/l), yeast extract (5.0 g/l), $K_2PHO_4$ (0.2 g/l), $CH_3COONa$ (2 g/l), and $MgCl_2$ (0.02 g/l).

• Applied Biological Chemistry
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• v.19 no.4
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• pp.219-226
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• 1976

To meet the need of protein feed and fine more efficient ways of returning waste to resources, we have carried out the study of the production of yeast for foods and feeds from the corn starch cake. The present study includes the method for acid-hydrolysis, the selection of yeast capable of utilizing hydrolyzate of the corn starch cake, and culture condition of Candida tropicalis under the liquid culture and the semisolid culture. Obtained results were as follows. 1. Hydrochloric acid was more excellent on the hydrolysis of the corn starch cake than sulfuric acid, and the yield of sugar was maximum, 57.2%, when the corn starch cake was hydrolyzed with 1.0% of hydrochloric acid at 2.0kg/cm for 30 minutes. 2. As the acid solution content was increased, more sugar was liberatedfrom the mixture, until the acid solution-substrate ratio reached 10:1. Beyond this point, no further increase was observed. To prepare the cultural medium of semisolid fermentation, a acid solution to substrate ratio of 3:1 appeared to be optimum. 3. Out of 6 yeast strains, Candida tropicalis had excellent growth on the hydrolyzate of the corn starch cake, and optimum temperature and initial pH were $30^{\circ}C$ and 6.0 respectively. 4. Optimum liquid medium of Candida tropicalis is ures 0.3%, potassium phosphate monobasic 0.15g and magnesium sulfate 0.04g in 100ml of the hydrolyzate of the corn starch cake, while optimum semisolid medium is ammonium chloride 0.4g, potassium phosphate monobasic 0.1%, magnesium sulfate 0.04%. 5. Candida tropicalis could assimilate the sugar in the hydrolyzate up to more than 88.75%, and a yield of dry yeast reached 19.13% to the corn starch cake under the liquid culture. 6. Compared to the that of the untreated corn starch cake, the cellulose content of the semisolid fermented cake decreased by 3.76% to 14.7%, whereas dry yeast contents increased by 13.89%.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.357-365
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• 2006

The investigations were conducted to find out the situation of fertilizer use and the contents of soil chemical components on summer vegetable crops at 791 farmers' upland fields located in the parts of Gangwon-do, Gyengsangbuk-do and Jeollabuk-do of alpine area. Major vegetable crops were potato, Chinese cabbage, radish, carrot, onion, and cabbage. From the location surroundings cultivated alpine vegetable crops, the orders were Gangwon-do>Gyeongsangbuk-do>Jeollabuk-do part in the sizes of a fie1d area and the height above sea level, and Jeollabuk-do>Gyeongsangbuk-do>Gangwon-do part in the slope degrees. The soil texture was of wide distribution on sandy loam soil for Gangwon-do(76%) and Jeollabuk-do part(64%), and 1oam(42%) and sandy loam soil(35%) for Gyeongsangbuk-do part. From the numbers of investigated fields, the distribution of slope degree was wider than those of height above sea level in relation to location surroundings. The upland soils of 785 fields cultivated vegetable crops were sampled at 0~15 cm of top soil before seeding or transplanting and analyzed. On an average, pH, organic matter, available phosphate and exchangeable potassium, calcium, magnesium of soil were 5.7, $27.6g\;kg^{-1}$, $765mg\;kg^{-1}$, $1.16cmol_c\;kg^{-1}$, $6.1cmol_c\;kg^{-1}$, and $1.6cmol_c\;kg^{-1}$, respectively. The average cation exchange capacity(CEC) of 120 sites in Gangwon-do part was $9.2cmol_c\;kg^{-1}$. The content of organic matter, exchangeable potassium, exchangeable calcium and exchangeable magnesium was higher, while that of available phosphate was lower with slope degrees. And the content of major chemical components in carrot soil was lower in comparison with other crop soils. The average levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizer of 785 Belds applied by farmers were 335, 198, 244, 12,680 and $1,750kg\;ha^{-1}$, respectively, for summer vegetable crops in alpine area. The average amounts of $N-P_2O_5-K_2O$ fertilizers applied by farmers in 785 Gelds of vegetable crops were higher 1.7~2.0-4.2~7.0-1.4~2.0 times on potato, 1.4~1.6-4.6~8.3-3.5~4.2 times on Chinese cabbage, and 1.2~1.3-4.2~7.2-3.0~3.61 times on radish than the rates of NPK fertilizers based on soil testing for each crop.

• Korean Journal of Community Nutrition
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• v.12 no.2
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• pp.133-141
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• 2007

Minerals play important roles in biological processes. Hair mineral analysis has the advantages of conveniences in sampling and observing the profiles of multiple minerals simultaneously. The purpose of this study was to compare hair mineral contents between urban and local middle school students, and to find out the relation with nutrient intakes and clinical symptoms. Ten nutritional minerals and 7 environmental mineral contents were analyzed in the hair samples of 44 and 37 male students who resided in urban and local area, respectively. And their nutrient intake and clinical symptom score were estimated from questionnaire. The average age, height, and weight were 15.1 years, 168.4 cm, 56.8 kg in urban subjects and 15.4 years, 169.1 cm, 61.9 kg in local subjects, respectively. The residence types were apartment (63.6%) and small-sized apartment (22.7%) in urban subjects and apartment (51.4%) and house (37.8%) in local subjects. The primary water sources were purified water (38.3%), running water (18.2%) in urban subjects and purified water (32.4%), underground water (27.0%) in local subjects, respectively. Daily energy and nutrient intakes were not significantly different between two groups. Among the surveyed 17 clinical symptoms, the scores of constipation, cold, anxieties and total score of clinical symptoms in urban subjects were significantly love. than those in local subjects. Hair contents of Na, Mg, Ca, Cu, V Al, As were significantly higher, while U was lower in urban subjects compared to those in rural subjects. Hair contents of Ni and U were significantly correlated with food intake, and Cr, V, Al, Sb, As, U showed a correlation with energy intake. Hair Mg level showed significantly negative correlation with total clinical symptom score. In conclusion, hair mineral profile between urban and local students was significantly different. And some of these minerals were significantly correlated with food and nutrient intakes. Especially hair magnesium was significantly correlated with total clinical symptom score. Therefore, hair mineral levels would be needed for more systematic study elucidating potentiality as a useful clinical tool.