• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.11-16
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• 2017

The frequency dependent input resistance observed in RF MOSFETs is analyzed in detail by deriving pole and zero frequency equations from a simplified input equivalent circuit. Using this theoretical analysis, we find that the reduction effect of the input resistance in the low frequency region arises from the channel resistance between source and pinch-off region in the saturation region. This channel resistance effect on the low frequency reduction of the input resistance is physically validated by performing small-signal equivalent circuit modeling with varying the channel resistance.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.9 no.2
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• pp.257-267
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• 2002

Purpose: Aquatic exercise program is known to have positive effects for health maintenance and improvement in inpatients with arthritis. Aquatic exercise program could be a way to obtain wellness in middle-aged women. However, there have been few studies to evaluate physical function. The purpose of this study was to identify the effects of aquatic exercise on physical health such as body weight, BMI, muscle strength (grip strength, pinch pressure), and flexibility in healthy middle-aged women. Method: The subjects of the study were fifty healthy middle-aged women (40-59 years) who had no experience with exercise. Twenty five subjects were assigned to the experimental group and 25 to the control group. An aquatic exercise program which consisted of approximately one hour of exercise in the water two days per week. for six weeks was given to the experimental group. Data were gathered from October 2000 to April 2001 using a questionnaire and physical function measure tool (pinch pressure, grip strength. weight. centimeter ruler). Data were analyzed with the SPSS win 10.0 using frequency, t-test, $x^2$ test, paired t-test. and ANCOVA. Result: The results of this study are as follows: There were significant differences in body weight, BMI, right, left grip strength and right and left pinch pressure between the two groups. Conclusion: From these results, it is concluded that the aquatic exercise program for healthy middle-aged women can be effective in increasing physical health in these women.

• Journal of the Korean Society of Physical Medicine
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• v.4 no.3
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• pp.201-207
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• 2009

Purpose：The purpose of this study was to investigate the effect of $\alpha$-wave music and art appreciation on hand function in stroke with hemiplegia. Methods：A total of 32 stroke with hemiplegia participated in this study experimental group(16 subjects) received $\alpha$-wave music and art appreciation with general neurologic therapy. Control group(16 subjects) received general neurologic therapy. All subjects were assessed for hand function(manual dexterity, power grip, pinch grip, two point discrimination(parm, finger), tactile sense(parm, finger) using a purdue pegboard, dynamometer, pinch gauge, two-point anethesiometer and semmes-weinstein monofilament wire. The data were analyzed using paired and independent t-test. Results：The results were as follows : 1. In the experimental group, manual dexterity were significantly increased between pre and post intervention(p<.05). 2. In the experimental group, tactile sesne in finger were sifnificantly increased between pre and post intervention(p<.05). Conclusion：The results of this study shows that $\alpha$-wave music and art appreciation affect the hand function of hemiplegic side with regard to manual dexterity and tactile sense.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1263-1268
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• 2008

In this paper, the low noise power amplifier for GaAs FET ATF-10136 is designed and fabricated with active bias circuit and self bias circuit. To supply most suitable voltage and current, active bias circuit is designed. Active biasing offers the advantage that variations in the pinch-off voltage($V_p$) and saturated drain current($I_{DSS}$) will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets a gate-source voltage($V_{gs}$) for the desired drain voltage and drain current. Using resistive decoupling circuits, a signal at low frequency is dissipated by a resistor. This design method increases the stability of the LNA, suitable for input stage matching and gate source bias. The LNA is fabricated on FR-4 substrate with active and self bias circuit, and integrated in aluminum housing. As a results, the characteristics of the active and self bias circuit LNA implemented more than 13 dB and 14 dB in gain, lower than 1 dB and 1.1 dB in noise figure, 1.7 and 1.8 input VSWR at normalized frequency $1.4{\sim}1.6$, respectively.

• Nuclear Engineering and Technology
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• v.31 no.5
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• pp.512-521
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• 1999

A feasibility study was performed to design an epithermal neutron beam for BNCT using the neutron of 2.45 MeV on the average produced from $^2H(d,n)^3$He reaction induced by plasma focus in the z-pinch instead of the conventional accelerator-based $^3H(d, n)^4$He neutron generator. Flux and spectrum were analyzed to use these neutrons as the neutron source for BNCT. Neutronic characteristics of several candidate materials in this neutron source were investigated Using MCNP Code, and $^7LiF$ ; 40%Al + 60%$AIF_3$, and Pb Were determined as moderator, filter, and reflector in an epithermal neutron beam design for BNCT, respectively. The skin-skull-brain ellipsoidal phantom, which consists of homogeneous regions of skin-, bone-, or brain-equivalent material, was used in order to assess the dosimetric effect in brain. An epithermal neutron beam design for BNCT was proposed by the repeated work with MCNP runs, and the dosimetric properties (AD, AR, ADDR, and Dose Components) calculated within the phantom showed that the neutron beam designed in this work is effective in tumor therapy. If the neutron source flux is high enough using the z-pinch plasma, BNCT using the neutron source produced from $^2H(d,n)^3$He reaction will be very feasible.

• Journal of muscle and joint health
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• v.14 no.2
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• pp.149-157
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• 2007

Purpose: The purpose of this study was to identify the effect of BeHaS exercise program on the upper body function(muscle strength, muscle endurance, flexibility) in middle-aged women. Method: Middle-aged women were recruited in the community the study was conducted from August 2005 to December 2005. Twenty-two experimental subjects were selected from P area, eighteen control subjects were selected from A area. The experimental group carried out the program two times a week for 12 weeks. Muscle strength(grip strength, pinch strength), muscle endurance (push-up), flexibility were measured. Data were analyzed with $x^2$-test, t-test, and ANCOVA using SPSS WIN 11.5. Results: 1) Left grip strength and right pinch strength of the experimental group were significant differences after the BeHaS exercise program. 2)Muscle endurance of the experimental group(t=3.14, p=0.015) was significant difference after the BeHaS exercise program. 3) Left and right flexibility showed no significant differences after the BeHaS exercise program. Conclusion: The results suggest that BeHaS exercise program would partially improve upper body function of middle-aged women. Further studies are necessary in order to determine the effects of flexibility after BeHaS exercise program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1153-1163
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• 2015

The purpose of this study is to investigate the effects of task-oriented activities on hand functions in patients with hand injuries. From December 2011 to October 2012, sixteen patients with hand injuries at C Hospital in Changwon, Gyeongsangnam-do, Korea were randomly divided into two groups. One group was subjected to task-oriented activity and the other to general exercise. Two groups performed each activity once a day, three times a week, for four weeks. The group with the task-oriented activities was provided with the tasks according to subject-preference based on the result of Canadian Occupational Performance Measure (COPM). To verify the effect of intervention, the following hand function measures were used: grip strength, pinch strength, and the range of opposition and abduction, Purdue pegboard test and Disabilities of the Arm, Shoulder and Hand (DASH). Both groups showed significant increase in all of the hand function measures after 4-week activities(p<.05). The task-oriented activity group was significantly different from the control group in powers for tip pinch, lateral pinch and three-jaw chuck pinch, Purdue pegboard test and DASH(p<.05) except in grip strength and the range of opposition and abduction suggesting better improvement in hand functions. This study shows that task-oriented activities improve the hand functions more effectively in patients with hand injuries.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.162-163
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• 2000

We have observed the short-channel effect, narrow-channel effect and small-geometry effect in terms of a variation of the threshold voltage. For a short-channel effect the threshold voltage was largely determined by the DIBL effect which stimulates more carrier injection in the channel by reducing the potential barrier between the source and channel. The effect becomes more significant for a shorter-channel device. However, the potential, field and current density distributions in the channel along the transverse direction showed a better uniformity for shorter-channel devices under the same voltage conditions. The uniformity of the current density distribution near the drain on the potential minimum point becomes worse with increasing the drain voltage due to the enhanced DIBL effect. This means that considerations for channel-width effect should be given due to the variation of the channel distributions for short-channel devices. For CCDs which are always operated at a pinch-off state the channel uniformity thus becomes significant since they often use a device structure with a channel length of > 4 ${\mu}{\textrm}{m}$ and a very high drain (or diffusion) voltage. (omitted)

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.21-28
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• 2008

In this paper, we suggest an analytical model that can derive the I-V characteristics in the saturation region of a short channel GaAs MESFET. Instead of the pinch-off concept that has been used in the conventional models we can derive the two-dimensional potential in the depletion region in order that the velocity saturation region cannot be pinched-off and the current continuity condition can be satisfied. Obtained expression for the velocity saturation length is expressed in terms of the total channel length, channel doping density, gate voltage, and drain voltage. Compared with the conventional channel length shortening models, the present model seems to be considerably accurate and more reasonable in explaining the Early effect.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.2
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• pp.152-159
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• 2010

We propose a semi-analytical current conduction model for depletion-mode n-type nanowire field-effect transistors (NWFETs) with top-gate structure. The NWFET model is based on an equivalent circuit consisting of two back-to-back Schottky diodes for the metal-semiconductor (MS) contacts and the intrinsic top-gate NWFET. The intrinsic top-gate NWFET model is derived from the current conduction mechanisms due to bulk charges through the center neutral region as well as of accumulation charges through the surface accumulation region, based on the electrostatic method, and thus it includes all current conduction mechanisms of the NWFET operating at various top-gate bias conditions. Our previously developed Schottky diode model is used for the MS contacts. The newly developed model is integrated into ADS, in which the intrinsic part of the NWFET is developed by utilizing the Symbolically Defined Device (SDD) for an equation-based nonlinear model. The results simulated from the newly developed NWFET model reproduce considerably well the reported experimental results.