• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.89-93
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• 2003

The failure of rock slopes were influenced by weathering, which causes change in the shear strength. The weathering is also directly related to slaking and swelling characteristics. In the paper, the core of diameter loom was obtained by digging on rock slope of Kong-ju in Korea and then EDX(Energy Dispersive X-ray spectrometer) analysis was carried out to verified element of chief rock-forming minerals. Uniaxial compression tests, slaking tests, and point load test are performed to study engineering characteristics of conglomerate and red shale. As a results of slaking test, slaking index of conglomerate indicate range of 85.11-99.58 and shale indicate 58.37-99.23. Therefore, it is recognized that the resistance of shale to weathering decreases in shallow depth and it greatly influences the strength of rock. The result of uniaxial compression test and Point load test show that the strength of sedimentary such as conglomerate and red shale has an influence on both weathering and saturation.

• Macromolecular Research
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• v.13 no.3
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• pp.194-205
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• 2005

The network structure of Ni-coated carbon black (NCB) composites filled with phenolic resin was investigated by means of using scanning electron microscopy, viscosity, interfacial tension, shrinkability, Flory-Huggins interaction parameters, and swelling index. The electrical properties of the composites have been characterized by measurement of the specific conductivity as a function of temperature. Additionally, the variation of conductivity with temperature for the composites has been reported and analyzed in terms of the dilution volume fraction, relative volume expansion, and barrier heights energy. The thermal stability of phenolic-NCB composites has been also studied by means of the voltage cycle processes. The experimental data of EMI wave shielding were analyzed and compared with theoretical calculations. The mechanical properties such as tensile strength, tensile modulus, hardness and elongation at break (EB) of NCB-phenolic resin composites were also investigated.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.66-72
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• 2013

In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.

• Korean Journal of Optics and Photonics
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• v.7 no.2
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• pp.96-100
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• 1996

Agfa 8E75 HD film is used to fabricate a film-type dichromated gelatin holographic combiner. The swelling factor of gelatin is controlled to increase the refractive-index modulation of hologram during the pre-processing steps. The characteristics of the reconstructed wavelength and the angular bandwidth are compared with those obtained with Kodak 649F plate.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.945-954
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• 2023

In this study, Sparassis crispa(cauliflower mushroom), which is rich in beta-glucan, was pulverized using ultrafine grinding technology for its potential utilization as a diverse food ingredient. The physical and antioxidant properties of cauliflower mushroom powder were evaluated at various grinding times. The results showed that as the grinding time of cauliflower mushroom increased, the average particle size significantly decreased (p<0.05). Additionally, the water-holding capacity, swelling capacity, and water solubility index of cauliflower mushroom increased significantly(p<0.05). Based on the analysis mentioned above, cauliflower mushroom prepared as a superfine powder for 5 minutes exhibited superior physical and chemical properties as well as antioxidant characteristics and is expected to be widely used in various foods.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.361-369
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• 2018

A manufacturing method has been devised to prepare novel heterogeneous cation exchange membranes by mixing ethylene vinyl acetate (EVA) copolymers with a commercial cation exchange resin. Optimum material characteristics, mixture ratios and manufacturing conditions have been worked out for achieving favorable membrane performance. Ion exchange capacity, electrical resistance, water uptake, swelling ratio and tensile strength properties were measured. SEM analysis was used to monitor morphology. Effects of vinyl acetate (VA) content, melt index (MI) and ion exchange resin content on properties of heterogeneous cation exchange membranes have been discussed. An application test was carried out by mounting a selected membrane in a membrane capacitive deionization (MCDI) system to investigate its desalination capability. 0.92 meq/g of ion exchange capacity, $8.7{\Omega}.cm^2$ of electrical resistance, $40kgf/cm^2$ of tensile strength, 19% of swelling ratio, 42% of water uptake, and 56.4% salt removal rate were achieved at best. VA content plays a leading role on the extent of physical properties and performance; however, MI is important for having uniform distribution of resin grains and achieving better ionic conductivity. Overall, manufacturing cost has been suppressed to 5-10% of that of homogeneous ion exchange membranes.

• Journal of Korean Neurosurgical Society
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• v.47 no.1
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• pp.1-6
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• 2010

Objective: On the basis of preoperative computed tomography (CT) scans, we studied the change of the size of anterior primary division (APD) of the L5 spinal root in the presence of foraminal/extraforaminal entrapment of the L5 spinal root. Methods: Two independent radiologists retrospectively reviewed the preoperative CT scans of 27 patients treated surgically and compared the sizes of the APDs on bilateral L5 spinal roots. If one side APO size was larger than the other side APD size, it was described as left or right "dominancy" and regarded this as "consensus (C)" in case that there was a consensus between the larger APD and the location of sciatica, and regarded as "non-consensus (NC)" in case that there was not a consensus. Oswestry Disability Index (ODI) scores were used for preoperative and postoperative evaluation. Results: On CT scans, twenty-one (77%) of 27 patients were the consensus group (APD swelling) and 6 (22%) were a non-consensus group (APD no swelling). In 9 patients with acute foraminal disc herniations, asymmetric enlargement of the APD on L5 spinal root was detected in all cases (100%) and detected in 11 (64%) of 17 patients with stenosis. Preoperative ODI score was 75-93 (mean 83) and postoperative 001 scores were improved to 13-36 (mean 21). The mean follow-up period was 6 months (range, 3-11 months). Conclusion: An asymmetric enlargement of the APD on L5 spinal root on CT scans is meaningfully associated with a foraminal or extraforaminal entrapment of the L5 spinal root on the lumbosacral junction.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.535-543
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• 2019

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and economical cost. On average, every 9m high embankment built with quarried/hauled soils cost $12600MJ.m^{-2}$ Embodied Energy (EE). A prospect of using mixed cutting-arising expansive soils with industrial/domestic wastes can reduce the carbon cost and ease the pressure on landfills. The widespread use of recycled materials has been extensively limited due to concerns over their long-term performance, generally low shear strength and stiffness. In this contribution, hydromechanical properties of a waste tyre sand-sized rubber (a mixture of polybutadiene, polyisoprene, elastomers, and styrene-butadiene) and expansive silt is studied, allowing the short- and long-term behaviour of optimum compacted composites to be better established. The inclusion of tyre shred substantially decreased the swelling potential/pressure and modestly lowered the compression index. Silt-Tyre powder replacement lowered the bulk density, allowing construction of lighter reinforced earth structures. The shear strength and stiffness decreased on addition of tyre powder, yet the contribution of matric suction to the shear strength remained constant for tyre shred contents up to 20%. Reinforced soils adopted a ductile post-peak plastic behaviour with enhanced failure strain, offering the opportunity to build more flexible subgrades as recommended for expansive soils. Residual water content and tyre shred content are directly correlated; tyre-reinforced silt showed a greater capacity of water storage (than natural silts) and hence a sustainable solution to waterlogging and surficial flooding particularly in urban settings. Crushed fine tyre shred mixed with expansive silts/sands at 15 to 20 wt% appear to offer the maximum reduction in swelling-shrinking properties at minimum cracking, strength loss and enhanced compressibility expenses.

• Journal of the Korean Wood Science and Technology
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• v.51 no.2
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• pp.133-144
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• 2023

Densification is an effective method for improving the physical and mechanical properties of low-density wood. However, the set-recovery of dimensions was found to be the problem of densified wood due to low fixation during the densification process. Alkali pretreatment before densification is thought to be a modification process to improve the dimensional stability of densified wood. In this research, the wood samples used were boiled in a 1.25 N sodium hydroxide (NaOH) solution at different times, followed by densification for 5 h at 100℃. The alkali pretreatment for 1, 3, and 5 h of boiling increased the dimensional stability of densified woods and anti-swelling efficiency values were 8.52%, 63.24%, and 48.94%, respectively. The boiling of wood in NaOH solution decreased the holocellulose content, as well as lignin to a lesser degree, and a lower crystallinity index was observed. The lower hydroxyl groups and a higher proportion of lignin in treated samples seem to have contributed to the high dimensional stability detected.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.7-12
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• 1989

The pain, swelling of salivary glands and dry mouth are not infrequent complication of the high dose radioiodine treatment in the patients with differentiated thyroid cancer. The purpose of this study was, by the dynamic salivary scintigraphy, to observe the change of the salivary function after the high dose $(150\sim200mci)$ radioiodine treatment. From May 1987 to April 1988, the dynamic salivary scintigraphy with 5mci of $^{99m}Tc-pertechnetate$ and gamma camera was performed before and 7 days after the radiolodine treatment in 7 patients with differentiated thyroid cancer. Just after the dynamic scintigraphy, the stimulation test with vitamin C solution of pH3.0 and poststirnulation scintigraphy were done, and the radioactivity uptake index, excretion fraction and salivary clearance after the stimulation were calculated for each gland. There was positive correlation between the radioactivity uptake index and excretion fraction after the stimulation. The salivary clearance after the stimulation was $18.96{\pm}8.95ml/min$ in the pretreatment state, and $14.37{\pm}7.7ml/min$ after the radioioine treatment. After the radioiodine treatment, the radioactivity uptake index, excretion fraction and salivary clearance after the stimulation were significantly reduced in the parotid glands, but only the excretion fraction was reduced in the submandibular glands. The more the pretreatment salivary clearance after the stimulation was, the % change after the treatment was smaller. Further studies on the relation between the radiation dose in the salivary glands and the change of their function, and the long-term observation for the recovery of function are expected.