• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.49-56
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• 2020

In this study, surface modification of CaCO₃ nanoparticles by a silane coupling agent propyltrimethoxysilane (PTMS) was conducted and the effect of surface hydrophobicity on the stability of foam and emulsion was studied in order to test the potential applicability as a foam stabilizer or an emulsifier. The surface modification of CaCO₃ nanoparticles by PTMS was confirmed by FT-IR, DSC and TGA analysis. The atomic concentration of CaCO₃ particle surface treated by PTMS has been also identified by using XRD and XPS analyses. Both floating tests and contact angle measurements were also performed to examine the effect of PTMS concentration on the surface modification of CaCO₃ nanoparticles.

• Journal of International Academy of Physical Therapy Research
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• v.3 no.2
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• pp.475-478
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• 2012

The purpose of this study is to identify the level of masseter muscle tension according to the levels of restricted movement and pain in the temporomandibular joint(TMJ), thereby verifying the fact that excessive masseter muscle tension can be a cause for restricted movement and pain in the TMJ. The subjects of this study were 81 men and women in their 20s and 30s, who feel uncomfortable with their masticatory function on the preferred chewing side. The subjects were measured in terms of the range of motion (ROM) and deviation of the TMJ and the degree of pain in the affected region. The ROM and deviation of the TMJ were measured using the Global Posture System(GPS) after instructing each subject to open his/her mouth to the fullest and taking photos of the subject with a digital camera. The tension of the masseter muscle was measured with a Pressure Threshold Meter(PTM). After the measurements, in order to compare the ROM of the TMJ, the subjects were divided into two groups based on the ROM of above 35mm and below 35mm. For the deviation and pain, based on the average of total subjects, the subjects were divided into two groups of above and below average. Thereafter, the levels of masseter muscle tension were compared between each pair of groups. According to the results, when each variable was compared between the respective two groups, in terms of the deviation, the pressure pain threshold(PPT) of the masseter muscle revealed a statistically significant difference(p<.05). However, the ROM and pain showed no statistically significant difference. Consequently, masseter muscle tension may cause restricted movement in the TMJ. In particular, the deviation and tension in the masseter muscle is considered to be a factor that causes deviation in the TMJ.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.63-70
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• 1990

The aim of this study has been to investigate the growth of the pharynx and sexual differences in the lateral cephalograms of Korean children. The material includes 173 cepalograms from two groups composed of 51 males aged 12.0 years and 39 females aged 12.2 years in group 2, and 45 males aged 7.4 years and 39 females aged 7.5 year in group 1, respectively. In order to study and measure the pharyngeal area the following skeletal landmarks were selected: S, N, A, Ptm, B, H, H', M, S-N, FH and CV, and the angle CV-FH was measured to provide a factor for correction of error resulting from improper head positioning of subjects, especially in relative positions of A and H, while radiography. For each variable the statistically treated data have been presented in the table Ⅱ, Ⅲ, Ⅳ. The main results are presented as follows: 1. In general, the measurements of male were larger than those of female in antero-posterior dimension of pharyngeal cavity, but all variables did not show significant sexual differences in both groups when evaluated statistically. 2. All of the measurements were larger in male than in female in vertical dimensions of pharyngeal cavity in group 2, and there were statistical significances of sexual differences in the variables except M-H', but all variables did not show significant sexual differences in group 1 when evaluated statistically. 3. The dimensional increase of the pharynx by the growth in the vertical dimensions was shown to be greater than in the antero-posterior dimensions in the both sexes.

• Economic and Environmental Geology
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• v.49 no.1
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• pp.23-30
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• 2016

Powder samples of natural lawsonite (Ca-lawsonite, $CaAl_2Si_2O_7(OH)_2{\cdot}H_2O$) was studied structurally up to 8 GPa at room temperature using monochromatic synchrotron X-ray powder diffraction and a diamond anvil cell (DAC) with a methanol : ethanol : water (16 : 3 : 1 by volume) mixture solution as a penetrating pressure transmitting medium (PTM). Upon pressure increase, lawsonite does not show any apparent pressure induced expansion (PIE) or phase transition. Pressure-volume data were fitted to a second-order Birch-Murnaghan equation of state using a fixed pressure derivative of 4 leading to a bulk modulus ($B_0$) of 146(6) GPa. This compression is further characterized to be isotropic with calculated linear compressibilities of ${\beta}^a=0.0022GPa^{-1}$, ${\beta}^b=0.0024GPa^{-1}$, and ${\beta}^c=0.0020GPa^{-1}$.

• Journal of Soil and Groundwater Environment
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• v.18 no.5
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• pp.15-25
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• 2013

In this study, two kinds of soil-based proficiency testing materials (PTMs), NICE-012L and NICE-012R were prepared and certified for Benzen, Toluene, Etylbenzene and Xylene with evaluation of uncertainties. In order to analyse BTEX (Benzen Toluene Etylbenzene Xylene) for the candidate materials, GC/MS was used after pretreatment according to methods of soil analysis by Ministry of Environment. For the homogeneity test among bottles in terms of candidate materials, ISO 13528 and IUPAC Protocol were used and according to the result, both candidate materials showed sufficient homogeneity. Also, the stability test over the candidate materials was accessed according to the ISO Guide 35 by classifying short-term and long-term stability and the result showed that both candidate materials showed decent stability. The reference values of the two candidate materials depending on BTEX components were derived from the average of the 11 samples that were used for verification of the samples' homogeneity. Uncertainty of measurement was combined by uchar that was caused by a characteristic value, $u_{bb}$ that was caused by between-bottle homogeneity, and $u_{stab}$ that was caused by stability, and then combined uncertainty ($u_{PTM}$) was multiplied to the coverage factor (k) derived from the effective degree of freedom from each factor that leads to expanded uncertainty (U) in about 95% of confidence level. The proficiency testing materials developed through this study were supplied to National Institute of Environmental Research (NIER) and utilized as an external proficiency testing materials for evaluating analysis capacity of soil agencies with specialty in terms of soil analysis approved by Minister of Environment.

• ETRI Journal
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• v.45 no.5
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• pp.910-921
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• 2023

In this study, we designed a 6T-SRAM cell using 16-nm CMOS process and analyzed the performance in terms of read-speed latency. The temperaturedependent Cu and multilayered graphene nanoribbon (MLGNR)-based nanointerconnect materials is used throughout the circuit (primarily bit/bit-bars [red lines] and word lines [write lines]). Here, the read speed analysis is performed with four different chip operating temperatures (150K, 250K, 350K, and 450K) using both Cu and graphene nanoribbon (GNR) nano-interconnects with different interconnect lengths (from 10 ㎛ to 100 ㎛), for reading-0 and reading-1 operations. To execute the reading operation, the CMOS technology, that is, the16-nm PTM-HPC model, and the16-nm interconnect technology, that is, ITRS-13, are used in this application. The complete design is simulated using TSPICE simulation tools (by Mentor Graphics). The read speed latency increases rapidly as interconnect length increases for both Cu and GNR interconnects. However, the Cu interconnect has three to six times more latency than the GNR. In addition, we observe that the reading speed latency for the GNR interconnect is ~10.29 ns for wide temperature variations (150K to 450K), whereas the reading speed latency for the Cu interconnect varies between ~32 ns and 65 ns for the same temperature ranges. The above analysis is useful for the design of next generation, high-speed memories using different nano-interconnect materials.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.399-411
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• 2000

This study was designed to evaluate the correlations between the morphology and growth of cranial base and the position of nasomaxillary complex and mandible in complete unilateral cleft lip and palate patients. Craniofacial skeletal morphology Pattern was analyzed on the lateral cephalometric radiographs of the 100 subjects of complete unilateral cleft lip and palate group and the 100 normal grower group and each group was divided three sub-groups by age-range like spheno-ethmoidal synchodrosis growing group, spheno-occipital synchondrosis growing group and finished synchondrosis growth group. These data were statistically analyzed to examine significant difference between both groups and between each sub-groups. The results of this study were as follows: 1. In complete unilateral cleft group, the length, thickness of clivus, and the rate of increase in length of clivus showed smaller amount by adolescence. The anterior length of cranial base and the rotation pattern of clivus with age showed no significant difference between two group. 2. In complete unilateral cleft group, nasomaxillary complex were located more posteriorly. This difference between two groups is larger by adolescent group than adult. Vertical position showed no significant difference between two groups. There was significant correlation between the cranial base of cleft group and the horizontal measurements(p<0.01). PtmS showed no significant increment in cleft group. This showed the deficiency of growth in posterior part of maxilla. 3. In mandible, there was no significant difference between normal group and complete unilateral cleft group but articular angle showed significantly smaller in cleft group than in normal one. And the measurements of nasomaxillary complex position, cranial base and the position of mandible had significant correlation(p<0.01).

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.280-290
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• 2012

This study was performed to establish the lateral cephalometric standards of Korean children for diagnosis of antero-posterior and vertical discrepancies of maxillofacial region. The lateral cephalometric radiographs were taken from 100 Korean children with normal occlusion, and then 15 measurements were statistically analysed. The results of this study were as follows : 1. Maxillary length of males was significantly greater than that of females (p < 0.05). There was strong correlation between maxillary and mandibular length (r = 0.625(M), 0.574(F)). 2. Lower facial height of males was significantly greater than that of females (p < 0.05). Furthermore, there was strong correlation between total facial height and upper facial height (r = 0.405(M), 0.417(F)) and very strong correlation between total facial height and lower facial height (r = 0.763(M), 0.787(F)). 3. All measurements for dento-alveolar relation showed no statistically significant sex difference. Maxillary length showed strong correlation with mandibular plane - lower incisor (r = 0.474(M), 0.426(F)) and mandibular plane - lower molar (r = 0.488(M), 0.499(F)).

• The korean journal of orthodontics
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• v.39 no.5
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• pp.330-336
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• 2009

Objective: To examine the differences in lateral cephalometric characteristics between patients with dental protrusion and crowding in order to determine what factors affect dental protrusion or crowding while both malocclusion types are caused by large tooth size. Methods: Twenty nine individuals with dental protrusion and 22 individuals with dental crowding were enrolled in this study. All subjects had larger teeth than average and Class I molar relationships. Craniofacial characteristics and hyoid bone positions were determined from lateral cephalograms and compared between the two groups. Results: In the comparisons of craniofacial characteristics, the measurements indicating maxillary length and facial convexity showed greater values in the protrusion group than in the crowding group. Comparisons of hyoid bone positions showed that the hyoid bone was positioned more anteriorly and superiorly in the protrusion group than in the crowding group. Conclusions: The results of the present study indicate that some craniofacial characteristics and tongue position may affect the development of dental protrusion or crowding; when an individual has large teeth, dental protrusion or crowding might be determined according to maxillary growth and tongue position.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.957-962
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• 2012

The principal objective of this study was to determine the effects of an ethanol extract of Polygonum multiflorum Thunberg (PMT) on body lipid metabolism in rats fed a high-cholesterol diet for 5 weeks. The rats were divided into 6 groups: a control group (I), a cholesterol-control group (II), a control group treated with 0.5% PMT (III), a control group treated with 1% PMT (IV), a cholesterol-control treated with 0.5% PMT (V), and a cholesterol-control group treated with 1% PMT (VI). Body weight gains and food efficiency ratios were not significantly different among the groups. The levels of serum blood glucose and triglycerides of the treated animals significantly decreased compared to the control and the cholesterol-control groups (p<0.05). There was a clear tendency of decreased LDL-cholesterol level in PMT-treated animals compared to the cholesterol-control group. However, no significant differences were observed in the serum HDL- and LDL-cholesterol levels. In the ratio of HDL-cholesterol to total cholesterol and HDL-cholesterol to LDL-cholesterol concentration, both the 0.5% PMT and 1% PTM extract intake groups had a higher percentage than in the control and cholesterol-control groups (p<0.05). In addition, the atherosclerotic index in serum was significantly lower in the PMT intake group than those in the group control and the cholesterol-control. These results indicated that the PMT extract was effective on the improvement of lipid metabolism in SD rats.