• Progress in Medical Physics
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• v.9 no.1
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• pp.11-21
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• 1998

Circular metal electrodes were vacuum-deposited with chromium on the both sides of Teflon-FEP and PET film characteristic of electret and the physical properties of the two polymers were observed during an irradiation by gamma-ray from $\^$60/Co. With the onset of irradiation of output 25.0 cGy/min the induced current increased rapidly for 2 sec, reached a maximum, and subsequently decreased. A steady-state induced current was reached about in 60 second. The dielectric constant and conductivity of Teflon-FEP were changed from 2.15 to 18.0 and from l${\times}$l0$\^$-17/ to 1.57${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/, respectively. For PET the dielectric constant was changed from 3 to 18.3 and the conductivity from 10$\^$-17/ to 1.65${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/. The increase of the radiation-induced steady state current I$\^$c/, permittivity $\varepsilon$ and conductivity $\sigma$ with output(4.0 cGy/min, 8.5 cGy/min, 15.6 cGy/min, 19.3 cGy/min) was observed. A series of independent measurements were also performed to evaluate reproducibility and revealed less than 1% deviation in a day and 3% deviation in a long term. Charge and current showed the dependence on the interval between measurements, the smaller the interval was, the bigger the difference between initial reading and next reading was. At least in 20 minutes of next reading reached an initial value. It may indicate that the polymers were exhibiting an electret state for a while. These results can be explained by the internal polarization associated with the production of electron-hole pairs by secondary electrons, the change of conductivity and the equilibrium due to recombination etc. Heating to the sample made the reading value increase in a short time, it may be interpreted that the internal polarization was released due to heating and it contributed the number of charge carriers to increase when the samples was again irradiated. The linearity and reproducibility of the samples with the applied voltage and absorbed dose and a large amount of charge measured per unit volume compared with the other chambers give the feasibility of a radiation detector and make it possible to reduce the volume of a detector.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.1
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• pp.75-82
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• 2000

In this paper, a new low power 16-bit ALU has been designed, fabricated and tested at the transistor level. The designed ALU performs 16 instructions and has a two-stage pipelined architecture. For the reduction of switched capacitance, the ELM adder of the proposed ALU is inactive while the logical operation is performed and P(propagation) block has a dual bus architecture. A new efficient P and G(generation) blocks are also proposed for the above ALU architecture. ELM adder, double-edge triggered register and the combination of logic style are used for low power consumption as well. As a result of simulations, the proposed architecture shows better power efficient than conventional architecture$^{[1,2]}$ as the number of logic operation to be performed is increased over that of arithmetic to logic operation to be performed is 7 to 3, compared to conventional architecture. The proposed ALU was fabricated with 0.6${\mu}m$ single-poly triple-metal CMOS process. As a result of chip test, the maximum operating frequency is 53MHz and power consumption is 33mW at 50MHz, 3.3V.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.105-111
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• 2007

In this paper, we designed and fabricated a 3-dB tandem coupler using air-bridge technology for millimeter-wane monolithic integrated circuits, operating at W-band($75{\sim}110\;GHz$) frequency. Tightly edge-coupled CPW line has low directivity due to different even-mode and odd-mode phase velocity. To overcome this disadvantage, a 3-dB tandem coupler which comprises the two-sectional weakly parallel-coupled lines with equal phase velocity was designed at W-band. The proposed coupler was fabricated using air-bridge technology to monolithically materialize the uniplanar coupler structure instead of conventional multilayer or wire bonded structure. From the measurements, the coupling coefficient of $2.9{\sim}3.6\;dB$ and the good phase difference of $91.2{\pm}2.9^{\circ}$ were obtained in broad frequency range of $75{\sim}100\;GHz$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.119-125
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• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.31-37
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• 2000

This study was designed to identify the ultrastructural changes of mouse endometrium during peri-implantation period and obtain the fundamental information for the establishment of 3-dimensional culture system of mouse endometrial cells in vitro. The used female ICR mice ($6{\sim}8$ wks) were conducted on pregnant. The biopsies were obtained from whole uterus at cycle day 1 (D1) and day 5 (D5) after hCG injection and mating. The biopsies materials were fixed 2.5% glutaraldehyde and 1% osmium tetroxide. Subsequently, for observation using light and transmission electron microscopy (LM and TEM), they were dehydrated and embedded in Epon and the embedded biopsies were sectioned and stained. For scanning electron microscopy (SEM), the fixed specimens were dehydrated, dried and coated with gold. 1) For LM, the biopsied materials at D5 (late secretory phase) were appeared the extended stromal layer by increased connective tissues and the fully developed endometrial glands and vessels compared with D1 (early secretory phase). 2) For TEM, the mouse endometrium was consisted of 3-layers, a simple polarized columnar epithelial cells, basement membrane and stromal cells. At D5, the distribution of microvilli, endoplasmic reticulum, Golgi body, lipid and glycogen deposits, secretory granules and surface area of basement membrane were increased. 3) For SEM, the degree of folding and microvilli of surface of mouse epithelial cells was became more and more according to the process of secretory phase, and at D5, implantation time of mouse, the appearance of pinopodes as a specific marker of uterine receptivity was found. The uterine pinopodes of mouse were found in narrow sites at the luminal surface, irregularity and appeared the different stages in the same sample. Therefore, these results indicated that the mouse endometrium was experienced dramatic morphological changes during peri-implantation period.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.261-270
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• 2019

The separation permeation characteristics of $N_2-O_2$ gas in air at cell membrane model of skin which irradiated by high energy electron(linac 6 MeV) were investigated. The cell membrane model of skin used in this experiment was a sulfonated polydimethyl siloxane(PDMS) non-porous membrane. The pressure range of $N_2$ and $O_2$ gas were appeared from $1kg_f/cm^2$ to $6kg_f/cm^2$. In this experiment(temperature $36.5^{\circ}C$), the permeation change of $N_2$ and $O_2$ gas in non-porous membrane by non-irradiation were found to be $1.19{\times}10^{-4}-2.43{\times}10^{-4}$, $1.72{\times}10^{-4}-2.6{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. That of $N_2$ and $O_2$ gas in non-porous membrane by irradiation were found to be $0.19{\times}10^{-4}-0.56{\times}10^{-4}$, $0.41{\times}10^{-4}-0.76{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. The irradiated membrane was significantly decreased about 4-10 times than membrane which was not irradiated. And ideal separation factor of $N_2$ and $O_2$ gas by non-irradiation was found to be from 1.32 to 0.42 and that of $N_2$ and $O_2$ gas by irradiation was found to be from 0.237 to 0.125. The irradiated membrane was significantly decreased about 4-5 times than membrane which was not irradiated. When the operation change(cut) and pressure ratio(Pr) by non-irradiation were about 0, One was increased to the oxygen enrichment and the other was decreased to the oxygen enrichment. The irradiated membrane was significantly decreased about 4-19 times than membrane which was not irradiated. As the pressure of $N_2$ and $O_2$ gas was increased, the selectivity was decreased. As separation permeation characteristics of $N_2-O_2$ gas in cell membrane model of skin were abnormal, cell damages were appeared at cell.

• Journal of the Korean Chemical Society
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• v.8 no.1
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• pp.20-24
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• 1964

The linear combination of bond orbitals method is used to investigate the reactivity of halomethanes in abstraction reactions by atoms. The activation energy is evaluated on the assumption that, in an activated complex, two electrons in a bond to be broken become completely isolated from the rest of the ${\sigma}$-electron systems. Such a model leads to an intuitively attractive concept that the interactions between the reactive bond and the neighboring bonds govern the reactivity of ${\sigma}$-electron systems. The resulting equation for the activation energy, ${\varepsilon},\;is:\;{\narepsilon}= ${\varepsilon}={\zeta}+$$${\sum}_{i=1}^3$${\eta}c-I,$ c-4 Here, subscript C-4 indicates the bond to be broken, while C-i represents the other three bonds surrounding the reactive bond; ξ is the activation energy of a hypothetical reaction of an isolated C-4 bond and an attacking atom; and ${\eta}$C-i,C-4 stems from the stabilizing interacting of C-4 bond with neighboring C-i bonds. A choie of η′s consistent with bond strength data simplifies the above equation to a form ${\varepsilon}={\zeta}\;+\;N{\eta}c$-H, C-4 where N denotes the number of C-H plus C-F bond in halomethanes. In agreement with this equation, experimental -values increase linearly with increasing N.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.159-165
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• 2008

In this paper the signal analysis of eddy current test using transmit-receive(T/R) pancake coil of ECT array probe using electromagnetic finite element method(FEM) is performed. For characteristics analysis, the notch defect is used. The depth of defect is 40[%] of steam generator tube thickness, and inside defect and outside defect are used as simulation examples. The signal analysis is performed according to the variation of receive coil position. The receive coil is positioned $0[^{\circ}]$, $30[^{\circ}]$, $60[^{\circ}]$, $90[^{\circ}]$ of circumferential position of transmit coil. To obtain e electromagnetic characteristics of robes, the governing equation is derived from Maxwell's equations, and the problem is solved using the 3-dimensional finite element method. The signal magnitude of inside defect is bigger than that of outside defect, and the signal difference can be seen according to the variation of position of receive coil. The experimental signal and numerical signal of ASME standard tube show similar results. The results in this paper can be helpful when the ECT signals from ECT array probe are evaluated and analyzed.

• Journal of the Korean Society for information Management
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• v.19 no.4
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• pp.96-111
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• 2002

A lot of accumulated data of many quantity exist within a institution or an organization, but most data is remained in form of standardization as each institution or organization. There are difficulty in exchange and share of information. New concept of knowledge information resource management to overcome this disadvantage was introduced, and the digitization of knowledge information resources to share and manage accumulated data is been doing. Specially, in science technic or education scholarship it, the tendency that importing XML to process necessary data to exchange and share of knowledge information resources structurally, and limitation of back for search and indexing or reusability is happened according as expression of great many mathematics used inside electron document of these sphere is processed to nonstructural data of image or text and so on. There is interest converged in processing of mathematics that use MathML to overcome this, and we require the solution to be able to process MathML easily and efficiently on structural document. In this paper, designed and implemented of XML document editing system which easy structural process of electronic document for knowledge information resources, and create and express MathML easily on structural document without expert knowledge about MathML.

• Analytical Science and Technology
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• v.11 no.1
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• pp.73-78
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• 1998

The reverse detection heteronuclear multiple quantum coherence, HMQC study of metcyano complex of horse myoglobin(MbCN) has provided the complete assignment of hyperfine shifted resonances of heme carbons attached with proton(s). The application of HMQC experiment to the paramagnetic low-spin MbCN gives clear $^1H$ and $^{13}C$ coherences for the paramagnetic amino acid residues as well as heme side chains, and can be extended to the low-spin paramagnetic hemoprotein derivative for the assignment of natural abundance $^{13}C$ resonances. This assignment strategy can avoid possible ambiguities that may result from the sole utilization of $^1H$ nuclear Overhauser effect for the assignment of heme $^1H$ signals resonating in the diamagnetic region. The resulting 2,4-vinyl ${\alpha}$-carbons and 7-propionate ${\beta}$-carbon follow anomalous anti-Curie behavior, and are indicative of incoplanarity with heme plane. Magnetic/electronic asymmetry of heme induced by proximal histidine(His) makes spread that the hyperfine shifted heme carbon resonances over the range of 250 ppm at $25^{\circ}C$. These heme carbon resonances would be the much more sensitive probe than those of proton resonances in analyzing the nature of heme electronic structure of myoglobin.