• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.423-430
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• 2002

The effects of UV-B and commercial grade pesticides (butachlor and carbofuran), individually and in combination, were studied on a variety of physiological processes of rice field cyanobacterium Anabaena doliolum. Butachlor was found to be $2-12\%$ more toxic than carbofuran and $4-24\%$ than UV-B on the growth, photosynthesis, lipid peroxidation, membrane permeability, and nitrogenase activity of the test cyanobacterium. Of the three photosynthesis inhibitors, the butachlor-induced inhibition of whole chain was approximately 3 and $21\%$ higher than carbofuran and UV-B, respectively. Although the interaction of the stress factors caused a significant inhibition (P<0.01), it was still less than the additive effect on the parameters investigated, except for PSI.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.2
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• pp.2661-2667
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• 1972

In the construction of earth dam, embankment, highway by filling, a compaction is to increase the density of applying pressure. By compaction interspaces between the soil graivos decrease so that density and adhesion increase but void and permeability decrease. Good compaction results in higher stablilty. The effect of the compaetion depends on a number of factors, of which the most important are soil charactesistics. Water content, and external force. In this study discussed is about sandy loam that since, with indentical force exerted and indentical compaction method, the effect of the compaction will be different due to the soil characteristics, the change of optimum moisture content and of maximum dry density by compaction yields difference in Compaction for a same sample.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.157-164
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• 2004

Air voids in hardened concrete have an important influence on concrete durability such as resistance of freezing and thawing, permeability and surface scaling resistance. Linear traverse method and point count method in ASTM standard method have been widely used to estimate the air void system in hardened concrete. However, these methods are not used at present time, because they are is exhausted much time and effort. In previous study, air voids system of concrete was estimated by spacing factor. The purpose of this study organizes image analysis method by analyzing air contents, air voids distributions by diameters, air voids system as well as spacing factors after hardened concrete. The experimental variables institute of depth of specimen(top, middle, bottom), air contents(AE contents 0, 0.01, 0.03%).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.310-315
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• 2000

In this paper, the problems of the external fixator that have developed for a distal radius fracture so far are analyzed, and accordingly, the characterizations, which must have a prototype, are arranged. C-Arm is used. This instrument makes it possible for the real play of the internal body by x-ray permeability. From this data, it is possible to induce important design factors. Finally, a basic mechanism, which has to be applied, is decided, and the Solid Edge program, which used a 3-D design tool, completes then total instrument design.

• Interdisciplinary Bio Central
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• v.3 no.4
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• pp.16.1-16.8
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• 2011

Defects in mitochondrial DNA (mtDNA) cause many human diseases and are critical factors that contribute to aging. The mechanisms of maternally-inherited mtDNA mutations are well studied. However, the role of acquired mutations during the aging process is still poorly understood. The most plausible mechanism is that increased reactive oxygen species (ROS) may affect the opening of mitochondrial voltage dependent anion channel (VDAC) and thus results in damage to mtDNA. This review focuses on recent trends in mtDNA research and the mutations that appear to be associated with increased ROS.

• Geotechnical Engineering
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• v.14 no.4
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• pp.61-76
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• 1998

Various kinds of reinforced soil methods have been developed by many researchers or companies for their economic merits mainly. These methods have generally used sandy soils which have high permeability as embanking or backfill material. That is because, if poor embanking materials, especially like a clayey soil which has very low permeability, are used in a reinforced soil embanking, and if excessive pore water pressure is produced by external factors, the friction resistance between reinforcing members and Boils decrease, as a result possible damage or collapse of the body of a reinforced embankment. In fact, clayey Boils can also be used as a embanking materials with reinforcement which has high permeable capacity, and are expected to be able to dissipate the excess pore water pressure effectively. In this study reinforcing effects have been examined through a serries of direct shear tests in which clayey soils are reinforced with nonwoven geotextiles of which permeability is very high and tensile strength is relatively weaker than geogrids which are usually used in reinforced soil wall. Even though such nonwoven geotextile are used as reinforcement of high saturated clayey soils. the test results show the possibility that nonwoven geoteztiles could be used as a reinforcement for reinforced soil walls effectively.

• International Journal of Highway Engineering
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• v.3 no.4 s.10
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• pp.93-103
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• 2001

This study focused on the field applicability evaluation of SB latex-modified concrete (LMC) for concrete bridge deck overlay using mobile mixer. The main experimental factors were water-cement ratio(31, 33, 35 37%), latex contents(0, 5, 10, 15, 20%), and fine aggregate ratio(55, 56, 57, 58%) in order to evaluate the workability, mechanical properties, and durability property of LMC. The slump loss, air content, compressive and flexible strength tests were used to evaluate LMC workability and strength properties. Also, the rapid chloride permeability test was used to evaluate the relative permeability of LMC. As a results, the LMC with enough workability and good quality was produced when it was mixed in field using mobile mixer, satisfying the target compressive strength and flexural strength. The required water-cement ratio of LMC for same workability when mixing with mobile mixer was less than that when mixing in laboratory. Increasing the amount of latex produced concrete with increased flexural strength by mobile mixer. The required cement-water ratios for same initial $19{\pm}3cm$ slump were 37% and 33% at laboratory and mobile mixer, respectively. The mobile mixer was accurately calibrated satisfying the required specification.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.77-82
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• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.85-94
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• 2012

Evaluation of the smear effect caused by mandrel penetration into soft ground for a vertical drain installation is very important to predict the consolidation time of soft ground improvement. 30 kinds of laboratory model tests considering in situ conditions were conducted to investigate the formation of a smear zone and the decrease of coefficient of permeability in the disturbed zone. Three types(C(clay):M(silt)=1:1, 0.5:0.5, and 0:1) of reconstituted samples were used for 3 dimensional smear zone test. An experimental study was performed focusing on length of mandrel penetration, mandrel shape and size, earth pressure, and ground condition(unit weight and grain size distributions). Laboratory test results show that the length of mandrel penetration is the most critical factor for the formation of smear zone. As a result, the ratio between diameter of the smear zone($d_s$) and that of mandrel($d_m$) at field using long mandrel becomes larger than conventional $d_s/d_m$. The ratio between $d_s$ and $d_m$ ranges from 1.89 and 2.48 with the sample at C:M=1:0. It was also found that the $d_s/d_m$ value with the round shape of the mandrel is smaller than that of diamond one. The value of $d_s/d_m$ decreased with larger mandrel size, lower unit weight, and higher earth pressure. However, higher silt content led to increase of $d_s/d_m$. The ratio between coefficient of horizontal permeability in the smear zone($k_{hs}$) and that of undisturbed zone($k_{ho}$) ranged from 0.70 to 0.85. The test results imply that factors and values affecting $k_{hs}/k_{ho}$ show similar tendency with $d_s/d_m$.

• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.937-946
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• 1995

In this research, the processing control of NiCuZn Ferrite has been developed. The relationship between initial permeability and bulk density of NiCuZn Ferrite with processing factors was studied. NiCuZn Ferrite, which calcinated at $700^{\circ}C$ for 3 hours, was ball milled for about 60 hours to make a size of $0.5\mu\textrm{m}$ followed by granulation using spray dryer. The physical properties and the magnetic properties of NiCuZn Ferrite were investigated with the processing factor, such as (i) granule size and forming pressure, and (ii) sintering temperature. The green density of NiCuZn Ferrite was largely depended on the forming pressure rather than its granule size. The green density of NiCuZn Ferrite was increased from $2.484\;g/cm^{3}$ to $3.002\;g/cm^{3}$ with increase in forming pressure. The bulk density of NiCuZn Ferrite was increased from $3.470\;g/cm^{3}$ to $4.754\;g/cm^{3}$ linearly with increase in sintering temperature. The relationship between initial permeability and bulk density of NiCuZn Ferrite was expressed with the empirical equation,$\mu_{i}=a+b_{\rho}+c_{\rho}^2$ at forming pressure and sintering temperature.