• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.1
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• pp.75-85
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• 2021

Evaluating the quantitative damage to rocks through acoustic emission (AE) has become a research focus. Most studies mainly used one or two AE parameters to evaluate the degree of damage, but several AE parameters have been rarely used. In this study, several data-driven models were employed to reflect the combined features of AE parameters. Through uniaxial compression tests, we obtained mechanical and AE-signal data for five granite specimens. The maximum amplitude, hits, counts, rise time, absolute energy, and initiation frequency expressed as the cumulative value were selected as input parameters. The result showed that gradient boosting (GB) was the best model among the support vector regression methods. When GB was applied to the testing data, the root-mean-square error and R between the predicted and actual values were 0.96 and 0.077, respectively. A parameter analysis was performed to capture the parameter significance. The result showed that cumulative absolute energy was the main parameter for damage prediction. Thus, AE has practical applicability in predicting rock damage without conducting mechanical tests. Based on the results, this study will be useful for monitoring the near-field rock mass of nuclear waste repository.

• Smart Structures and Systems
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• v.28 no.6
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• pp.761-777
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• 2021

This study presents a numerical investigation on the sensitivity of electromechanical (EM) impedance responses to inner damaged concrete of a prestressed anchorage zone. Firstly, the Ottosen yield criterion is selected to simulate the plasticity behavior of the concrete anchorage zone under the compressive loading. Secondly, several overloading cases are selected to analyze inner damage formations in the concrete of the anchorage zone. Using a finite element (FE) model of the anchorage zone, the relationship between applied forces and stresses is analyzed to illustrate inner plasticity regions in concrete induced by the overloading. Thirdly, EM impedance responses of surface-mounted PZT (lead-zirconate-titanate) sensors are numerically acquired before and after concrete damage occurrence in the anchorage zone. The variation of impedance responses is estimated using the RMSD (root-mean-square-deviation) damage metric to quantify the sensitivity of the signals to inner damaged concrete. Lastly, a novel PZT skin, which can measure impedance signatures in predetermined frequency ranges, is designed for the anchorage zone to sensitively monitor the EM impedance signals of the inner damaged concrete. The feasibility of the proposed method is numerically evaluated for a series of damage cases of the anchorage zone. The results reveal that the proposed impedance-based method is promising for monitoring inner damaged concrete in anchorage zones.

• The Korean Journal of Soil Zoology
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• v.8 no.1_2
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• pp.27-31
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• 2003

This study has been conducted to assess and analyze the damage of Codonopsis lanceolata by differential inoculation levels of Meloidogyne hapla in pot and plot. As the density of M. hapla increased, early growth of C. lanceolata was inhibited 60% in vine and 54% in root. However, growth of C. lanceolata was not remarkably different by density of M. hapla in the plot test. This result may be attribute to low density of M. hapla in the plot.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.09a
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• pp.79-94
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• 2002

Root cause -Thermal expansion coefficient mismatch -Tape warpage -Initial die crack (die roughness) Guideline for failure prevention -Optimized tape/Substrate design for minimizing the warpage -Fine surface of die backside Root cause -Thermal expansion coefficient mismatch - Repetitive bending of a signal trace during TC cycle - Solder mask damage Guideline for failure prevention - Increase of trace width - Don't make signal trace passing the die edge - Proper material selection with thick substrate core Root cause -Thermal expansion coefficient mismatch -Creep deformation of solder joint(shear/normal) -Material degradation Guideline for failure Prevention -Increase of solder ball size -Proper selection of the PCB/Substrate thickness -Optimal design of the ball array -Solder mask opening type : NSMD -In some case, LGA type is better

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.4
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• pp.681-687
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• 2010

Sibjeondaebo-tang (SJDBT) is an oriental medicinal prescription for the treatments of diverse symptoms including neurological disorders. In order to investigate its potential role for neural regulation following nerve injury, neurite outgrowth of dorsal root ganglion (DRG) neurons in culture was investigated. In DRG neurons which were preconditioned by sciatic nerve injury, neurite outgrowth was enhanced by SJDBT treatment. When preconditioned DRG neurons were co-cultured with astrocytes prepared from injured spinal cord tissue, neurite outgrowth was similarly facilitated by SJDBT. Astrocytes in co-culture showed more intense signals of vimentin protein by SJDBT compared to saline control. Sukjihwang (SJH), a conventional herbal component of SJDBT prescription, did not induce any significant changes in neurite extension of DRG neurons compared to control cells. These data suggest that SJDBT may be the therapeutic agent for nervous system disorders related to nerve damage.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.426-429
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• 1999

When the tooth avulsion occur in accidents the drying damage to the periodontal ligament has extremely detrimental effects on healing. Pulp necrosis always occurs after an avulsion injury, but revascularization can only take place in teeth with immature apexes. Therefore complications after avulsion injuries are common, and treatment must be carried out in a timely and correct fashion to prevent or limit these complications. Every effort should be made to replant the tooth within the first 15 to 20 minutes. If doubt exists that the tooth can be replanted adequately, the tooth should quickly be stored in an appropriate medium until the patient can get to the dental office for replantation. A complication of inflammatory root resorption is occurred by bacterial infection of periodontal ligament and dental pulp. Therefore aseptic endodontic treatment must be carried out in a timely and systemic antibiotics given at the time of replantation and before endodontic treatment are effective in preventing bacterial invasion. Further studies are needed to establish the clinical importance of preparation of the socket and root.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.362-369
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• 1990

In order to determine the mechanism of saline stress, forage plants were irrigated with sea water. Saline stress was investigated on photosynthesis, root respiration, evapotranspiration and visual symptoms. All crops showed increased relative evapotranspiration and relative photosynthesis under low temperature (11-16$^{\circ}C$) rather than high temperature (22-24$^{\circ}C$). The correlation coefficients calculated for each crop between relative evapotranspiration and root respiration were 0.996$\^$**/ for orchard grass, 0.828$\^$*/ for alfalfa and 0.963$\^$**/ for white clover. No significant correlation coefficient between relative evapotranspiration and root repiration was found for the tall fescue. The effects of OED spray on the evapotranspiration and root respiration of crops in the sea watered pots were low compared with those in the fresh watered pots. When OED was sprayed and zeolite was used, the evapotranspiration and root respiration were low compared with check pots and sand pots. The root damage due to sea water treatment was characterized by brown colored root cortex in orchard grass and tall fescue, and water penetration of root cortex in alfalfa and white clover.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.366-378
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• 1998

Thermocondensation root canal filling technique have been used to fill accessary canals or to obtain homogeneous root caral fillings. But these thermocondensation technique inevitably produce heat in the canal which can be transmitted through the dentin and cementum and consequently damage periodontal ligamental cells and osteoblasts. In this study, System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$(Analytic technology, WA.D.S.A.) was used to evaluate the reaction of periodontal ligament tissue to "Continous Wave condensation technique" introduced by Buchanan, and the transmitted root surface temperature was measured according to measured root thicknesses. 12 Mandibular incisors of two adult dogs were used for the experiment. 6 controls were filled by lateral condensation technique with sealer.3 specimens were apically filled by Continuous Wave technique at $200^{\circ}C$ for 5 seconds and remaining 3 specimens were additionally backfilled using System $B^{TM}$ at $100^{\circ}C$ for 20 seconds. Six weeks later, the dogs were sacrificed and the teeth stained with Hematoxylin and Eosin for histologic examination. 6 extracted human teeth were used to measure the transmitted temperature. After cutting off the crown, the canals were prepared and divided into 3 groups with root thickness of 1.5mm, 1.0mm, 0.5mm, 2 teeth in each group. Inside each root canal, System $B^{TM}$ was heated as with the temperature for the apically condensed and the back filled group, and the transmitted heat was measured on the external surface of the root. The temperature of System $B^{TM}$ heat spreader at $200^{\circ}C$ and $100^{\circ}C$ was also measured at root temperature. It can be concluded as follows: 1. In the thin area (200-$250{\mu}m$) of the root, root resorption could be seen even with heating at $200^{\circ}C$ for 5 seconds. 2. When the spreader was heated at $200^{\circ}C$ for 5 seconds and additionally at $100^{\circ}C$ for 20 seconds for backfill, all teeth showed root resorption regardless of their root thickness. 3. The transmitted external root surface temperature was higher as the root thickness decreased and as the heating time increased. In the thermocompaction technique using System $B^{TM}$, the spreader should be heated for the minimal time and used only in the apical area. The heated spreader shouldn't inserted to the binding point of the canal and backfilling should be done with other means of minimally heated gutta percha technique.

• Herbal Formula Science
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• v.13 no.2
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• pp.141-151
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• 2005

From the tuberous root of Aconitum carmichaeli Debx.(Ranunculaceae), the main root is called as common monkhood mother root and the later root is called as the prepared aconite root. From the prepared aconite root. Looking at the processing method of the prepared aconite root, it is divided into Yeombuja (prepared aconite root processed in salt) and heuksoonpyeon (baekbupyeon) following the processing method after removing the soil and this is a way of processing the prepared aconite root without damage it. The recently produced raw prepared aconite root is easily damaged, thus it shall be preserved in salt to have the crystal shape on the surface of the prepared aconite root and store and transport in firmly solidified yeombuja condition. Therefore, yeombuja shall remove the salt before use and requires processing for use but heuksoonpyeon or baekbupyeon may use immediately. For the succession of the unique processing techniques of our ancestors, there has to be studies on the techniques. Prepared aconite root is generally used as holy medicines to cure the yang depletion syndrome, kidney-yang deficiency syndrome, and obstruction of qi in the chest syndrome. However, they are the substances with toxicity. It is contemplated that the contents of processing are broadly understood through the document on the processing method, and based on such foundation, the systematic set and proof on the documents are made along with the addition of the contemporary scientific theory and technology to develop the traditional processing technology to maximize the treatment effect and safety of prepared aconite root. In this study, the historic data and records on the processing method of latteral root of aconitum carmichaeli Debx will be rearranged to contribute to the standardization of medicinal herbs, maximization of efficacy and minimization of the side effects.

• The Journal of Korean Academy of Prosthodontics
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• v.9 no.1
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• pp.29-34
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• 1969

Occlusal force is a critical factor affecting the condition and structure of the periodontium. When the occlusal forces exceed the physiologic adaptive capacity of the tissues, tissue damage ensues. Such damage is referred to as trauma from occlusion. Excessive pressure causes compression, degeneration and realignment of the periodontal ligament fibers so that they are paralleled perpendicular to the tooth and bone. By inducing excessive occlusal forces with a high amalgam filling on rat's molar, the author observed histologic alterations of the periodontal ligament fibers by means of Hematoxylin-eosin, Van Gieson and Aldenyde fuchsin stainings. The results of the study were observed as follows: 1) The excessive occlusal forces altered arrangement of the collagenous fibers. 2) The arrangement of the oblique fibers showed appreciable differences between the control group and the group subjected to 10 days experimental trauma from occlusion. 3) The realignment of the transseptal fibers was not found. 4) The arrangement of the oblique fibers after 15 days of trauma from occusion was similar to that of 10 days experimental group. 5) The oxytalan fibers were more abundant at the cementum rather than at the alveolar bone. 6) The excessive occlusal forces produced funnel-shaped widening of the oxytalan fibers, which followed wavy course. 7) The oxytalan fibers appeared to be distributed mainly around the middle third of the root rather than that of the apical third of the root during the experimental trauma from occlusion.