• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.79-87
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• 1984

The purpose of the study is to determine the effects of Zn in lead poisoning rats by way of examining interaction mechanism of Pb and Zn. The fifty-five rats were Pb divided into four groups such as Zn group, group, Pb and Zn group, and control group. The rats of Zn group and of Zn and Pb group were subdivided into four groups by dose of Zn respectively 250mg/l, 500mg/l, 1, 000mg/l and 2, 000 mg/l. The rats having been fed the above mentioned chemicals, were weighed every five days for fifty-five days, and the subjects were slaughtered for measuring $\delta$-ALAD activities in blood and the accumulation amount of the chemicals in livers and kidneys. The results of the study are summarized as following 1. As for body weight gains, those of the control group rats were the highest, and those of Pb group the lowest. 2. $\delta$-ALAD activities of Pb group showed the tendency of decrease in comparison with those of control group. In Zn group, the subgroups of 250mg/l and 500mg/l showed higher activities than control group, whereas the subgroups of 1, 000mg/l and 2.000mg/l showed lower. 3. Hb value of Pb group was lower than that of control group. In Zn group, Hb value of the groups of 250mg/l and 500mg/l was a little higher than that of control group, while that of the groups of 1, 000mg/l and 2, 000mg/l was lower. 4. The amount of Pb and Zn accumulated in liver was much higher than in kidney. The amount of Pb accumulated in organs of Zn and Pb group decreased gradually in contrast to high concentration of Zn.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.495-510
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• 2015

The applications of water jet cutting (WJC) in coal mine have progressed slowly. In this paper, we analyzed the possibility and reasonableness of WJC application to pressure relief in hard coal seam, simulated the distributive characteristics of stress and energy fields suffered by hard coal roadway wallrock and the internal relationships of the fields to the instability due to WJC (including horizontal radial slot and vertical annular slot) on roadway wallrock. The results showed that: (1) WJC can unload hard coal seam effectively by inducing stress release and energy dissipation in coal mass near its slots; its annular slots also can block or weaken stress and energy transfer in coal mass; (2) the two slots may cause "the beam structure" and "the small pillar skeleton", and "the layered energy reservoir structure", respectively, which lead to the increase in stress concentration and energy accumulation in coal element mass near the slots; (3) the reasonable design and optimization of slots' positions and their combination not only can significantly reduce the scope of stress concentration and energy accumulation, but also destroy coal mass structure on a larger scale to force stress to transfer deeper coal mass.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.302-309
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• 2017

The ageing of XLPE cable insulation will lead to the accelerating accumulation of space charge, which will greatly affect the safe operation of the HVDC cable. In order to investigate the influence of different ageing modes on the space charge distribution of the HVDC cable, thermal stressed, electrical stressed and electro-thermal stressed endurance tests were carried out on the XLPE peelings. The tested XLPE peelings were obtained from 160kV HVDC cable insulation. The endurance tests were carried at thermal stress of 363K, electrical stress of 20kV/mm DC and a combination of both. The Pulsed Electro-Acoustic (PEA) method was used to measure the space charge distribution of the samples. The influences of ageing on the trap energy distribution were analyzed based on the isothermal relaxation theory and the decay characteristics of the space charge. The results showed that thermal ageing would help to improve the crystalline morphologies of the XLPE at the early stage. The total amount of space charge decreased compared to the ones before thermal ageing. The long term of electrical stress would result in the cleavage of polymer molecule chains which would intensify the accumulation of space charge and increase the density and depth of electron traps. With a combination of electrical and thermal stress, the injection and migration of space charge were more significant. Besides, the depth and density of electron traps increased rapidly with the increase of endurance time.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2089-2098
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• 2015

With the continuous development in insulation of electrical equipment design, the reliability of the system has been enhanced. However, in the manufacturing process and during operation under continues stresses introduce local defects, such as voids between interfaces that can responsible to occurrence of partial discharge (PD), electric field distortion and accumulation of charges. These defects may lead to localize corrosion and material degradation of insulation system, and a serious threat to the equipment. A model of three layers of PI film with air gap is presented to understand the influence of interface and voids on exploitation conditions such as strong electrical field, PD activity and charge movement. The analytical analysis, and experimental results are good agreement and show that the lose contact between interfaces accumulate more residual charges and in consequences increase the electric field intensity and accelerates internal discharges. These residual charges are trapped charges, injected by the electrodes has often same polarity, so the electric field in cavities increases significantly and thus partial discharge inception voltage (PDIV) decreases. Contrary, number of PD discharge quantity increases due to interface. Interfacial polarization effect has opposite impact on electric field and PDIV as compare to void.

• Environmental Engineering Research
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• v.18 no.3
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• pp.151-156
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• 2013

Several soil properties were studied from three young created mitigation wetlands (<10 years old), which were hydrologically comparable in the Piedmont region of Virginia. The properties included soil organic matter (SOM), soil organic carbon (SOC), pH, gravimetric soil moisture, and bulk density ($D_b$). No significant differences were found in the soil properties between the wetlands, except SOM and SOC. SOM and SOC indicated a slight increase with wetland age; the increase was more evident with SOC. Only about a half of SOC variability found in the wetlands was explained by SOM ($R^2$ = 0.499, p < 0.05). The majority of the ratios of SOM to SOC for these silt-loam soils ranged from 2.0 to 3.5, which was higher than the 1.724 Van Bemmelen factor, commonly applied for the conversion of SOM into SOC in estimating the carbon storage or accumulation capacity of wetlands. The results may caution the use of the conversion factor, which may lead to an overestimation of carbon sequestration potentials of newly created wetlands. SOC, but not SOM, was also correlated to $D_b$, which indicates soil compaction typical of most created wetlands that might limit vegetation growth and biomass production, eventually affecting carbon accumulation in the created wetlands.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.179-186
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• 1998

Effects of lead(Pb) and calcium(Ca) on growth responses, accumulation of heavy metals and nitrogen fixation activities of Melilotus suaveolens seedlings were quantitatively analyzed during growing period. Pb contents of the root treated with 30, 100 ppm Pb and 100 ppm Pb added 100 ppm Ca were 54.1, 90.9 and 26.1 folds higher than that of the control, respectively, at pH 4.2 in 28th days, and heavy metal content of plant increased with increasing of pH and Pb concentration. The melilot plant was classified as a Pb accumulator by higher accumulation of Pb in shoot than that of root. Pb treatments resulted in inhibiton of height and chlorophyll contet, and Ca treatment increased height and chlorophyll content insignificantly at pH 4.2 in 28 days. The plant biomass reduced 49, 60 and 54% at pH 4.2 and 47,53 and 50% at pH 6.5, respectively, by 30, 100 ppm Pb and 100 ppm Pb added 100 ppm Ca treatment. Specific nitrogen fixation of nodules reduced 68.4% and 46.6% by 100 ppm Pb treatment and 3.7% and 24.9% by 100 ppm Pb added 100 ppm Ca at pH 4.2 and pH 6.5, respectively, so Ca inhibited significantly Pb activity and toxicity in acdic pH. Nodule formation were reduced to 33, 33 and 50% at pH 4.2 and 50, 33 and 38% at pH 6.5 by 30, 100 ppm Pb and 100 ppm Pb added 100 ppm Ca, respectively.

• Journal of Yeungnam Medical Science
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• v.32 no.1
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• pp.42-46
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• 2015

Gouty ulcer can be caused by the accumulation of clumps of uric acid in body tissues that lead to acute or chronic inflammation at sites of accumulation. Furthermore, tophi-inhibiting granulation tissue may form a canal that channels microbial infection from the underlying involved joint space, and thus, presents the risk of osteomyelitis development. Accordingly, gouty ulcer must be treated appropriately. In this case, refractory wounds on gouty ulcers at the left shin and left radial ankle were treated by surgical debridement. Negative-pressure wound therapy was used successfully to prevent post-operative delayed wound healing.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.675-684
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• 2011

In nature, the overall effect of heavy metals on the biota can be influenced by a number of environmental factors like soil characteristics and air pollution by elevated $CO_2$. Pillbugs (Isopoda, Armadillium vulgare) take up heavy metals with their food and store them mainly in the vesicles of hepatopancreas. They accumulate certain metals, occur in relatively large numbers, are easily collected and identified, and provide sufficient material for analysis. The species are decomposing litter well and soil impurities into N and P. Therefore, it has been suggested that total body concentration of metals in pillbugs could be positively correlated to the levels of environmental exposure and that pillbugs could be used as biological indicators of metal pollution and global change by $CO_2$. The aim of the study is to determine effects of heavy metal concentrations in soil and elevated $CO_2$ on pillbugs' body accumulation of heavy metal and growth rate. In this study, the concentrations of six metals (Fe, Mg Cu, Zn, Pb, Cd) have been determined. Pillbugs (N=287) were collected at five sites during Jul-Aug, 2006. Cu and Zn concentrations in the body were much higher than in the soils(1.39-41.70 times). This indicated that bioaccumulation of some of the heavy metals were increasing in the food-chain. The high bioconcentration of lead in Sangam may be partly associated with reclaimed land uses.

• Mycobiology
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• v.49 no.4
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• pp.396-405
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• 2021

Cinnamomum migao plants often face different degrees of drought in karst habitats, which can lead to plants' death, especially in the seedling stage. Widespread of arbuscular mycorrhizal (AM) fungi in karst soils have the potential to address this drought, which is a threat to C. migao seedlings. We inoculated C. migao seedlings with spores from Glomus lamellosum and Glomus etunicatum, two AM fungi widely distributed in karst soils, to observe seedling growth response after simulated drought. Our results showed that 40 g of G. lamellosum and G. etunicatum significantly promoted the growth of C. migao seedlings, 120 days after inoculation. Following a 15-day drought treatment, root colonization of the seedlings with G. lamellosum or G. etunicatum had lower the accumulation of malondialdehyde (MDA) and increased the accumulation of enzymes and osmotic substances in the seedlings. The relative water content in different organs (roots, stems, and leaves) of the drought-stressed seedlings was higher in plants with G. lamellosum or G. etunicatum than in plants without AM fungi colonization. Our results showed that inoculation with AM fungi was an effective means to improve the drought resistance of C. migao seedlings.

• Korean Journal of Plant Resources
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• v.32 no.1
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• pp.1-8
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• 2019

This study was performed to select the effective plant for phytoremediation of heavy metal contaminated areas. After cultivation of fifteen Compositae plants on soil contaminated with heavy metals for 8 weeks, the growth response and accumulation ability of each parts for heavy metal, such as arsenic, cadmium, copper, lead, and zinc were analyzed. Except Adiantum capillus-veneris, growth of Aster incisus, Coreopsis drumondii), Dendranthema indicum, Saussurea pulchella were relatively fine. Arsenic accumulation ability was the highest by Artemisia gmelini ($25.52mg{\cdot}kg^{-1}$ DW) in underground part, and D. sichotense ($3.35mg{\cdot}kg^{-1}$) in aerial part. Cadmium was the highest by Aster magnus ($2.50mg{\cdot}kg^{-1}$) in aerial part. Aerial and underground part of S. pulchella showed the highest copper accumulation (24.29, $99.92mg{\cdot}kg^{-1}$). In lead, 1.43 (A. magnus)${\sim}5.00mg{\cdot}kg^{-1}$ (S. deltoides) were accumulated in aerial part among fifteen Compositae plants. Aster hayatae ($140.09mg{\cdot}kg^{-1}$), Aster yomena ($109.07mg{\cdot}kg^{-1}$), A. magnus ($100.21mg{\cdot}kg^{-1}$) are absorbed more than $100mg{\cdot}kg^{-1}$ of Zinc. Therefore, they are considered to be phytoremediation material of zinc contaminated areas.