• Journal of the Korean Mathematical Society
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• v.50 no.6
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• pp.1271-1290
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• 2013

Let M be a fixed left R-module. For a left R-module X, we introduce the notion of M-prime (resp. M-semiprime) submodule of X such that in the case M=R, it coincides with prime (resp. semiprime) submodule of X. Other concepts encountered in the general theory are M-$m$-system sets, M-$n$-system sets, M-prime radical and M-Baer's lower nilradical of modules. Relationships between these concepts and basic properties are established. In particular, we identify certain submodules of M, called "primeM-ideals", that play a role analogous to that of prime (two-sided) ideals in the ring R. Using this definition, we show that if M satisfies condition H (defined later) and $Hom_R(M,X){\neq}0$ for all modules X in the category ${\sigma}[M]$, then there is a one-to-one correspondence between isomorphism classes of indecomposable M-injective modules in ${\sigma}[M]$ and prime M-ideals of M. Also, we investigate the prime M-ideals, M-prime submodules and M-prime radical of Artinian modules.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.342-342
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• 2010

We have investigated an Au intercalated monolayer graphene on Ni(111) using angle-resolved photoemission spectroscopy (ARPES), high resolution photoemission spectroscopy (HRPES), and low energy electron diffraction (LEED) at the 3A2 ARUPS beamline in Pohang Accelerator Laboratory. We find the monolayer graphene is well grown on the Ni(111) surface by the adsorption of acetylene. However, the graphene does not show the characteristic $\pi$ band near the Fermi level due to its strong interaction with the underlying substrate. When Au is adsorbed on the surface and then annealed at high temperature, we observe that Au is intercalated underneath the monolayer graphene. The process of the Au intercalation was monitored by HRPES of corresponding Au 4f and C 1s core levels as well as the electronic structure of the $\sigma$, $\pi$ states at $\Gamma$, K points. The $\sigma$, $\pi$ bands of graphene shift towards the Fermi level and the $\pi$ band is clearly observed at K point after the intercalation of full monolayer Au. The full width at half maximum (FWHM) of the C 1s peak narrows to approximately 0.42 eV after intercalation. These results imply that the interaction between the graphene and substrate is considerably weakened after the Au intercalation. We will discuss the graphene is really closer to ideal free standing graphene suggested recently.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.75-78
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• 2003

In this paper, a second-order 3-bit DSM using DWA(Data Weighted Averaging) algorithm is designed for bluetooth Zero-IF Receiver. The designed circuit has two integrators using a designed OTA, nonoverlapping two-phase clerk generator, 3-bit A/D converter, DWA algorithm and 3-bit D/A converter An ideal model of second-order lowpass DSM with a 3-bit quantizer was configured by using MATLAB, and each coefficients and design specification of each blocks were determined to have 10-bit resolution in 1MHz channel bandwidth. The designed second-order 3-blt lowpass DSM has maximum SNR of 74dB and power consumption is 50mW at 3.3V.

• Structural Engineering and Mechanics
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• v.88 no.3
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• pp.201-208
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• 2023

In this work, the effect of the correction fibers direction on the efficiency of repairing damaged composite plates was highlighted. The composite plates studied in this work consist of eight layers of graphite/epoxy, while the patch used in this repair consists of four layers of the same type. The results obtained in this work, whether with regard to the experimental or analytical side, showed that the fibers orientation affects the repair efficiency, so the closer the angle of fibers inclination is to the tensile strength direction, the performance of the composite material is ideal. Hence, we conclude that the composite materials with longitudinal fibers (Parallel to tensile strength) is the most powerful and efficient material in performance.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.148-153
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• 1999

Baikdu-san was a very active volcano during the Cenozoic era and is believed to be formed in late Cenozoic era. Recently it was also reported that there was a major eruption in or around 1002 A.D. and there are evidences which indicate that it is still an active volcano and a potential volcanic hazard. Remote sensing techniques have been widely used to monitor various natural hazards, including volcanic hazards. However, during an active volcanic eruption, volcanic ash can basically cover the sky and often blocks the solar radiation preventing any use of optical sensors. Synthetic aperture radar(SAR) is an ideal tool to monitor the volcanic activities and lava flows, because the wavelength of the microwave signal is considerably longer that the average volcanic ash particle size. In this study we have utilized several sets of SAR data to evaluate the utility of the space-borne SAR system. The data sets include JERS-1(L-band) SAR, and RADARSAT(C-band) data which included both standard mode and the ScanSAR mode data sets. We also utilized several sets of auxiliary data such as local geological maps and JERS-1 OPS data. The routine preprocessing and image processing steps were applied to these data sets before any attempts of classifying and mapping surface geological features. Although we computed sigma nought ($\sigma$$^{0}$) values far the standard mode RADARSAT data, the utility of sigma nought image was minimal in this study. Application of various types of classification algorithms to identify and map several stages of volcanic flows was not very successful. Although this research is still in progress, the following preliminary conclusions could be made: (1) sigma nought (RADARSAT standard mode data) and DN (JERS-1 SAR and RADARSAT ScanSAR data) have limited usefulness for distinguishing early basalt lava flows from late trachyte flows or later trachyte flows from the old basement granitic rocks around Baikdu-san volcano, (2) surface geological structure features such as several faults and volcanic lava flow channels can easily be identified and mapped, and (3) routine application of unsupervised classification methods cannot be used for mapping any types of surface lava flow patterns.

• Journal of Aquaculture
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• v.7 no.4
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• pp.239-249
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• 1994

This study was conducted to elucidate mixing characteristics of the media to dertermine hydraulic model parameters of the three phase fluidized bed for the water quality management of aquaculture. The volume and H/D ratio of the reactor were 1.76 Liter and 10.9, respectively. The experimental results showed that variance $(\sigma^2)$ and dispersion number $(D/{\mu}L)$ were above 0.47 and $0.35\~\infty$, respectively. Therefore, the condition of the reactor was almost ideal complete mixing. The dependence of the overall oxygen-transfer coefficient $(K_{La})$ on each experimental variables through a multple linear regression was given by the following equation ; $$K_{La}\;=\;44.9(D_i/D_c)^{-0.4611}\;A_f^{0.8622}\;C_m^{-0.0746}\;d_p^{-0.4302}$$

• Journal of the Korean Chemical Society
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• v.34 no.2
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• pp.130-135
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• 1990

The title compound (C13H17NO2S) is monoclinic, space group P21/a, with a = 13.756 (3), b = 9.310(4), c = 21.305(3) $\AA$, $\beta$ = 95.0。, Z = 8, V = 2718.11 $\AA$3, Dc = 1.23$g·{\cdot}cm-3$, (Mo k$\alpha$) = 0.71069$\AA$,$\mu$ = 2.18 cm-1, F(000) = 1071.86, T = 298, R = 0.085 for 2935 unique observed reflections with I >2.0$\sigma$(I). The structure was solved by direct methods. The C-H bond lengths and the methyl groups are fixed and refined as their ideal geometry by allowing to ride on the parent atoms. Both molecules A and B have almost same structures except for two terminal ethyl groups. The ethylene-like skeleton including the nitro group in one molecule is nearly perpendicular to the plane of the methylbenzene group and two ethyl groups form a cis-type structure which has the dfferent orientations between two molecules; in the molecule A, two terminal methyl groups being the opposite directional arrangement against the plane of its skeleton, while in the B, with the same directional structure from its plane. The molecules in the crystal are packed together by non-bonded van der Waals forces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.23-23
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• 2009

It has been challenging to increase the thermoelectric figure of merit ($ZT=S^2{\sigma}T/\kappa$) of materials, which determine the efficiency of thermoelectric devices, because the three parameters Seebeck coefficient (S), electrical conductivity ($\sigma$), and thermal conductivity ($\kappa$) of bulk materials are inter-dependent. With the development of nanotechnology, ZT values of nanostructured materials are predicted to be enhanced by classical size effects and quantum confinement effects. In particular, Bi nanowires were suggested as one of ideal thermoelectric materials due to the expected quantum confinement effects for the simultaneous increase in Sand. In this work, we have investigated the thermal conductivity of individual single crystalline Bi nanowires with d = 98 nm and d = 327 nm in the temperature range 40 - 300 K using MEMS devices. The for the Bi nanowire with d = 98 nm was observed to be ~ 1.6 W/m-K at 300 K, which is much lower than that of Bi bulk (8 W/m-K at 300 K). This indicates that the thermal conductivity of the Bi suppressed due to enhanced surface boundary scattering in one-dimensional structures. Our results suggest that Bi nanowires grown by stress-induced method can be used for high-efficiency thermoelectric devices.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.1-9
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• 1990

Cholesteryl pentanoate $(C_{32}O_2H_{54})$ is orthorhombic, space group $P2_12_12_1$, with a = 21.930(3), b = 21.404(3), c = 6.419(5) $\AA$, Z = 4, V = 3012.8(5)$\AA$$^3$, $D_c$ = 1.04 g$cm^{-3}$, ${\lambda}(Mo\; K{\alpha}$ = 0.71069 $\AA$, $\mu$ = 0.58 $cm^{-1}$, F(000) = 1048, T = 298, R = 0.086 for 1502 unique observed reflections with I > 1.0 $\sigma$ (I). The structure was solved by direct methods and refined by cascade diagonal least-squares refinement. The C-H bond lengths and the methyl groups are fixed and refined as their ideal geometry. A comparison with other cholesteryl esters gives normal structure for the tetracyclic ring, while the tail regions of the side chain and the ester group which stands on end, show a variation from their normal values, presumably due to thermal effects. The molecules are stacked together by non-bonded van der Waals forces with the shortest intermolecular distance of 3.529 $\AA$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.157-159
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• 2010

Most digital cameras apply a Charge Coupled Device(CCD) Sensor or a Complementary Metal Oxide Semiconductor(COMS) Sensor. And the images captured these sensors include unwanted noises. In this paper, we proposed a method of the Noise Reduction(NR) about noise reduction or recovery in the image. The proposed NR method is related to Bandwidth of the Low Pass Filter(LPF). For improvement of NR, we were changing the filter coefficient of the LPF. The results of simulations with various filter coefficients, [1 2 1] in the LPF and [-1 2 -1] in the High Pass Filter(HPF) have ideal frequency bandwidth and high performance. We proposed a filter coefficient [1 2 1] and [-1 2 -1] in the LPF and the HPF respectively.