• Journal of Educational Research in Mathematics
• /
• v.22 no.2
• /
• pp.261-275
• /
• 2012

There are some geometry achievement standards presented indistinctly in middle school mathematics curriculum revised in 2011. In this study, indistinctness of some geometric topics presented indistinctly such as symbol $\overline{AB}{\perp}\overline{CD}$ simple construction, properties of congruent plane figures, solid of revolution, determination condition of the triangle, justification, center of similarity, position of similarity, middle point connection theorem in triangle, Pythagorean theorem, properties of inscribed angle are discussed. The following three agenda is suggested as conclusions for the development of next middle school mathematics curriculum. First is a resolving unclarity of curriculum. Second is an issuing an authoritative commentary for mathematics curriculum. Third is a developing curriculum based on the accumulation of sufficient researches.

• Ocean Systems Engineering
• /
• v.13 no.2
• /
• pp.123-146
• /
• 2023

In this paper, Moore-Gibson-Thompson theory of thermoelasticity is considered to investigate the fundamental solution and vibration of plane wave in an isotropic photothermoelastic solid. The governing equations are made dimensionless for further investigation. The dimensionless equations are expressed in terms of elementary functions by assuming time harmonic variation of the field variables (displacement, temperature distribution and carrier density distribution). Fundamental solutions are constructed for the system of equations for steady oscillation. Also some preliminary properties of the solution are explored. In the second part, the vibration of plane waves are examined by expressing the governing equation for two dimensional case. It is found that for the non-trivial solution of the equation yield that there exist three longitudinal waves which advance with the distinct speed, and one transverse wave which is free from thermal and carrier density response. The impact of various models (i)Moore-Gibson-Thomson thermoelastic (MGTE)(2019), (ii) Lord and Shulman's (LS)(1967) , (iii) Green and Naghdi type-II(GN-II)(1993) and (iv) Green and Naghdi type-III(GN-III)(1992) on the attributes of waves i.e., phase velocity, attenuation coefficient, specific loss and penetration depth are elaborated by plotting various figures of physical quantities. Various particular cases of interest are also deduced from the present investigations. The results obtained can be used to delineate various semiconductor elements during the coupled thermal, plasma and elastic wave and also find the application in the material and engineering sciences.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.1 s.53
• /
• pp.125-134
• /
• 2009

This paper deals with the free vibrations of circular strip foundations which have uniform solid rectangular cross-section. The ground which supports circular strips was modeled as the two parameter elastic foundation. Differential equations governing the flexural-torsional free vibrations of circular strips supported by such foundation were derived, and solved numerically for obtaining the natural frequencies and mode shapes. Boundary condition of free-free ends was considered for numerical examples. Four lowest natural frequencies according to the variations of five system parameters i.e. subtended angle, depth ratio, contact ratio, elasticity ratio and soil parameter are reported in the non-dimensional forms. Also, typical mode shapes of both deformations and stress resultants are presented in the figures. Experiment was conducted for validating the theory developed in this study.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.2
• /
• pp.471-474
• /
• 2015

Background: Male and female breast cancers were investigated for variation in the clinicopathologic characteristics and expression of steroid hormone receptors in the northeast of Iran. Materials and Methods: Tumor specimens of 17 males and 338 females with breast cancer were collected at the hospitals of Mashhad University of Medical Sciences. Immunohistochemical expression of hormone receptors and clinicopathologic features of breast cancer were compared between two groups. Results: The mean age in men was 15 years higher than women (p=0.000). Males and females were mainly in stage II and III respectively (p=0.007). Although more than 60% of male and female patients were grade II, the respective figures for grade I and III were 25% and 12.5% in men but 7.1% and 27.2% in women respectively (p=0.025). ER was significantly more positive in men against women; 82.3% versus 53.4% (p=0.016). The related measures for PR was 58.8% and 50.3%, respectively (p=0.424). Males also showed significantly more ER expression than postmenopausal females; 82.3% versus 48.9% (p=0.010). Conclusions: Breast cancer in males and females contrasted in age at diagnosis, histological type, stage, grade and ER expression which emphasize they are separate diseases with different behaviors.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.4
• /
• pp.938-945
• /
• 2004

On the relationship between the red tide occurrence and the oceanographic factors in the middle coastal area in the South Sea of Korea, the favorable oceanographic conditions for the red tide formation are considered as follows； the calm weather increases sea water temperature in summer and early-fall which the red tide occurs frequently, and the heavy precipitation brings some riverine water to ween: low salinity, high suspended solid, low phosphorus and high nitrogen, respectively. We decided the potential areas in the coastal zones vulnerable to the red tide occurrence based on the limited factors controlling the growth of phytoplankton. By using GIS through the overlap for three subject figures (phosphorus, nitrogen and suspended solids), it was founded that the potential areas are the Yeosu∼Dolsan coast, the Gamak bay, the Namhae coast, the Narodo coast, the Goheung and Deukryang bay. This result has very well coincided to the results of the satellite and in-situ data.

• Applied Science and Convergence Technology
• /
• v.25 no.5
• /
• pp.88-91
• /
• 2016

The $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+xwt%PbO systems at temperature of $1250^{\circ}C$ for 4 hours was successful synthesized. In this study, PbO-doped $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$ systems with non-linear behaviors showed ordering-degree dependence at the low temperature range were prepared using the columbite precursor method. And the characteristic of remnant polarization vs. electric field were analyzed. The pyroelectric, dielectric and piezoelectric properties of partially disordered $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+xwt%PbO solid solutions were studied as a function of temperature, frequency, and electric field. It showed distinct features of temperature dependent of pyroelectric coefficient, spontaneous polarization and dielectric constant at about $50^{\circ}C$. The figure of merit was calculated as pyroelectric coefficient, dielectric constant and dissipation factor. It was found that the high voltage responsivity FV, high detectivity FD were $0.0373m^2/C$ and $0.6735{\times}10^{-4}Pa{-1/2}$, respectively, in the $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+3.0 wt%PbO system.

• Journal of Adhesion and Interface
• /
• v.15 no.2
• /
• pp.57-62
• /
• 2014

Pythagolas rule was used for investigation of static contact angle in particular figures. Static contact angle measurement was important to evaluate the wettability between solid and liquid. Optimum measurement method and standardization of calculation for static contact angle were investigated for practical application. Optimum diameter of droplet for static contact angle measurement was confirmed as 1 mm. Contact angle measurement using Pythagolas rule was also used to calculate advancing, receding angle and wettability of different surface condition. At last, it was concluded that the Pythagolas rule method was more accurate than general lineation method for static contact angle measurement.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5A
• /
• pp.477-486
• /
• 2009

This paper deals with the strongest static arches with the solid regular polygon cross-section. Both span length and volume of arch are always held constant regardless the shape functions of cross-sectional depth of regular polygon. The normal stresses acting on such arches are calculated when both static vertical and horizontal point loads are subjected. By using the calculating results of stresses, the optimal shapes of strongest static arches are obtained, under which the maximum normal stress become to be minimum. For determining the redundant of such indeterminate arches, the least work theorem is adopted. As the numerical results, the configurations, i.e. section ratios, of the strongest static arches are reported in tables and figures. The results of this study can be utilized in the field of the minimum weight design of the arch structures.

• Journal of The Korean Association For Science Education
• /
• v.28 no.4
• /
• pp.291-301
• /
• 2008

The purpose of this study was to investigate explanations of high school chemistry II textbooks and the diversity of chemistry major teachers' thinking types related to dilute solution properties for finding the sources of students' difficulties. Eight kinds of textbooks were analyzed, and the teachers' thoughts were searched by a questionnaire developed for inquiring teachers' preference of explanation types. We analyzed teachers' responses from individual interviews after the questionnaire to discern their deeper thoughts. From the results, it was found that the explanations of the textbooks were not clear enough to have scientific conceptions. The figures and explanations of the textbooks do not match either. It was also found that chemistry major teachers' thoughts were not solid when they suffered cognitive confliction by different situation with their thoughts.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.17 no.1
• /
• pp.11-17
• /
• 2013

Purpose: The use of SUV which should be normalized by lean body mass (LBM) is recommended for PET response criteria in solid tumors. LBM which was determined by whole body CT was used for SUV normalization (SUL) in this study. The purpose of the present study was to assess interobserver and intraobserver reproducibility of SUL measurements in reference organs. Materials and Methods: F-18 FDG PET/CT was conducted on 52 subjects and LBMs were directly determine by whole body CT for normalization of SUV. The 3 cm diameter spherical VOI, $1\times2$ cm cylindrical VOI, 2 cm diameter spherical VOI were placed in the liver, descending aorta and spleen, respectively. Experienced two observers measured SULmax and SULmean in each organ. Repeated measurements were conducted two weeks apart by observer 1 blind to previous results. Similarly, measurements were conducted on the same patients by observer 2. For assessing reproducibility(or repeatability), the paired t-test, Pearson's correlation coefficients (CC), and technical error of measurement (TEM) were calculated. Results: For interobserver reproducibility in liver SULmax and SULmean, no significant differences were found between observers(paired t-test, P=0.536, 0.293, respectively). CC and TEM for liver SULmean were 0.909 (P=0.000) and 0.067 SUL unit, respectively. Corresponding figures for liver SULmax were 0.882 (P=0.000) and 0.117 SUL unit, respectively. For intraobserver reproducibility in liver SULmax and SULmean, no significant differences were observed within observer1 (paired t-test, P=0.374, 0.268, respectively). CC and TEM for liver SULmean were 0.924 (P=0.000) and 0.061 SUL, respectively. Corresponding figures for liver SULmax were 0.908 (P=0.000) and 0.104 SUL, respectively. Similarly, no significant differences were found in SULmax and SULmean of the spleen and aorta between observers. Conclusion: The current study demonstrated that both SULmean and SULmax measurements in normal reference organs are highly reproducible. Reproducibility of SULmean in reference organs were slightly better than SULmax. Interobsever technical error of measurement was less than 0.10 SUL unit for liver SULmean, and 0.12 SUL unit for liver SULmax. Intraobsever technical error of measurement was less than 0.07 SUL unit for liver SULmean, and 0.11 SUL unit for liver SULmax.