• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1161-1170
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• 2000

Objective : The transverse hippocampal slice is one of the most commonly studied in vitro models of mammalian brain physiology. However, despite its broad usage, there has been no standardization of slice preparation techniques or recording condition. It is well known that variations in recording conditions can result in profound different effects to neuronal responses. Evoked field potentials, recorded extracellularly, were used to investigate the effects of variations in hippocampal slice preparation protocol on hypoxia responses of CA1 neurones. Material & Methods : Before hypoxic injury, hippocampal slices were incubated for 4 hours. During incubation period, the slices were placed in a incubation chamber($21^{\circ}C$) for recovery from preparation injury and then transferred to recording chamber($34^{\circ}C$) for more recovery and baseline electric recording with current stimulation(0.1Hz). Various time periods in incubation chamber and recording chamber were applied to each experimental group(group 1=60min : 180min, group 2=90min : 150min, group 3=180min : 60min, time in incubation chamber : time in recording chamber) before 10 min hypoxia produced by replacing 95% $O_2$+5% $CO_2$ mixed gas to 95% $N_2$+5% $CO_2$ gas. Calcium, Magnesium ions and several drugs effecting on glutamate receptor also were studied. Recoveries from hypoxic injury of hippocampal slices were estimated by percent recovery of population spike(PS). Statistic analysis of study were performed using paired t-test. Results : The percent recovery of PS after 10min hypoxia was considerably enhanced by increasing the period of current stimulation during incubation period before hypoxic injury. Temperature effect on the result of this experiment was also studied(group 4) but the result from this showed no statistic significance. Low magnesium ion concentration of artificial CSF(Mg-free aCSF) during incubation period enhanced the recovery of PS but low calcium (calcium-free) and high magnesium ion concentration(2mM) reduced it after hypoxic injury. L-glutamate($100{\mu}M$) and AP-5($50{\mu}M$) had no effect on the recovery of PS but CNQX($10{\mu}M$) in artificial CSF during incubation period markedly enhanced the recovery of PS. Co-treatment of AP-5($50{\mu}M$), CNQX($10{\mu}M$) and high magnesium concentration(2mM) enhanced recovery of PS in immediate following period of hypoxic injury but the effect of cotreatment after then decayed rapidly and lost statistic significance. Conclusions : Judging from above results, the condition of baseline recording is important in observing the recovery of population spike after hypoxia, and the time and the condition should be controled more strictly to obtain reliable results.

• Korean Journal of Computational Design and Engineering
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• v.7 no.3
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• pp.148-156
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• 2002

Most Rapid Prototyping (RP) processes adopt a solid Computer Aided Design (CAD) model, which will be sliced into thin layers of constant thickness in the building direction. Each cross-sectional layer is successively deposited and, simultaneously, bonded onto the previous layer; and eventually the stacked layers from a physical part of the model. A new RP process, the transfer-type Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-ST), has been developed to reduce building time and to improve the surface finish of parts with the thick layers and a sloping surface. This paper describes the generation of Unit Shape Layer (USL), the cutting path data of the linen. hotwire cutter for the VLM-ST process. USL is a three-dimensional layer with a thickness of more than 1 mm and a side slope, and it is the basic unit of cutting and building in the VLM-ST process. USL includes data such as layer thickness, positional coordinates, side angles of each layer, hotwire cutting speed, the heat input to the hotwire, and reference shape. The procedure of generating USL is as follows: (1)Generation of the mid-slice from the CAD model, (2)Conversion of the mid-slice into a simply connected domain, (3)Generation to the reference shape for the mid-slice, (4)Calculation of the rotation angle of the hotwire of the cutting system.

• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.103-106
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• 2007

In order to construct a Video Database, shot change detection should be made first. But, because these processes are not automated perfectly, we need a lot of time and efforts now. And, there are many shot change detection algorithms, which can't always insure the perfect result because of the editing effects such as cut, wipe, and dissolves used in film production. Therefore, in order to receive the exact shot change, It needs the verification and correction by manual processing at any cost. Spatiotemporal slice is a simple image condensing method for the content changes of video. The editing effects are expressed on the Spatiotemporal slice in the visually noticed form of vertical line, diagonal line, curved line and gradual color changes, etc. Accordingly the parts doubted as a shot change can be easily detected by the change of the Spatiotemporal slice without replaying the video. The system proposed in this study makes it possible to delete the false detected key frames, and create the undetected key frames on the Spatiotemporal slice.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.705-711
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• 2019

Currently, the brain CT scan of the latest equipment lacks the study of parameter change and dose change and especially of noise, uniformity analysis and dose change. Therefore, this study attempted to study the phenomenon that occurs at this time by analyzing tube voltage, slice thickness, and pitch change in exposure parameters when using high specification CT. Experimental results show that uniformity is better when using high voltage, thick slice thickness selection, and minimum pitch. As a result of the combination, the most uniformity condition was 140 kVp, 10 mm and pitch 0.5. Noise was found to be improved regardless of pitch by increasing tube voltage and slice thickness. The radiation dose increased linearly with tube voltage and pitch. Therefore, the results of this study will serve as a reference for the use of High specification brain CT.

• Journal of Biosystems Engineering
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• v.37 no.1
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• pp.36-43
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• 2012

Purpose: Drying characteristics of the sliced carrot and green pumpkin were investigated by using the waste heat dryer. Methods: The effects of drying temperature ($T$) and slice thickness affecting drying time were analyzed. Mathematical models for the drying curves were determined with statistical analysis of drying data. Effective diffusivity was determined for the slices of carrot and green pumpkin under various drying conditions. Results: Drying time was reduced at the drying conditions of thinner slice and higher drying temperature. Moisture ratio ($MR$) according to drying time ($t$) was well presented as an exponential function at all of drying conditions for the slices of carrot and green pumpkin with the determination coefficient ($r^2$) of >0.99. The values of effective diffusivity ($D_{ff}$) of the slices for carrot and green pumpkin were increased with increasing the drying temperature. The relationship between Ln($D_{ff}$) and $1/T$ was linear with the determination coefficient ($r^2$) of >0.97. Conclusions: Drying model was well established as an exponential function at all of drying conditions for drying samples.

• Communications of the Korean Mathematical Society
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• v.33 no.1
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• pp.305-315
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• 2018

This note provides a study of lightlike hypersurfaces of a generalized Robertson-Walker(GRW) space-time with a certain screen distribution, which are integrable and have good properties. Focus is to investigate geometric features from the relation of the second fundamental forms between lightlike hypersurfaces and leaves of the integrable screen distribution. Also, we shall apply those results on lightlike hypersurfaces of a GRW space-time to lightlike hypersurfaces of a Robertson-Walker(RW) space-time.

• Journal of Acupuncture Research
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• v.21 no.4
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• pp.31-51
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• 2004

Objective: The propose of this study is to investigate the characteristics of combustion in indirect moxibustion with garlic. Methods: We observed the characteristics of combustion by the variations of the thickness(3mm, 4mm, 5mm) of a slice for indirect moxibustion with garlic and mass(80mg, 100mg, 120mg) of moxa cone and existence of holes. The temperature of indirect moxibustion for garlic insulation with holes was higher than temperature of indirect moxibustion for garlic insulation without holes. Combustions time in the preheating period is about 1 minute, it varies by the existence of holes, the thickness of a slice for indirect moxibustion with garlic, and the density of moxa cone. Results: Maximum temperature of heating period was $38.7{\sim}46.2^{\circ}C$, combustion time in the heating period was 118~164sec and maximum ascending temperature gradient was $0.102{\sim}0.264^{\circ}C/sec$. Retaining period was shorter than heating period and stimulus of heating retains more, because it is higher than body temperature. By this report, indirect moxibustion with garlic is more effective with holes and the appropriate thickness of a slice for indirect moxibustion with garlic is 3.5~4mm. It is appropriate that the diameter of moxa cone is 8mm and height of that is 10mm. With this condition, effective combustion period is 120sec, maximum temperature is $42{\sim}44^{\circ}C$, maximum ascending temperature gradient is $0.14{\sim}0.16^{\circ}C/sec$. It is necessary to study clinical correlations for more accurate quantitative standard.

• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.200-207
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• 1994

A biosensor for the measurement of L-glutamine has been constructed by immobilizing the slice of Wistar rat kidney and it's organelle on $NH_3$ gas-sensing electrode. The effects of pH, buffer solution, temperature and thickness of slice were investigated in order to optimize electrode response. The tissue sensor had the linearity in the range of L-glutamine concentration $8.0{\times}10^{-5}{\sim}1.0{\times}10^{-2} M$ with a slope of 53.8 mV/decade in 0.05 M phosphate buffer solution, pH 7.8 at $30^{\circ}C$, and optimum thickness of slice and response time were 30 ${\mu}m$ and 3∼5 min, respectively. The organelle sensor showed the linearity within L-glutamine concentration range of $1.2{\times}10^{-4}{\sim}5.0{\times}10^{-3} M$ with a slope of 54.0 mV/decade in 0.05 M phosphate buffer solution, pH 7.8 at $30^{\circ}C$, and response time was 6∼7 min, respectively. Thus, it is clear that the tissue and organelle sensor will be useful for L-glutamine measurements.

• Journal of Communications and Networks
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• v.11 no.1
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• pp.1-10
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• 2009

In this paper, we propose a chip-level detection and a spectral-slice scheme for the tunable-transmitter/fixed-receiver (TTFR)-based asynchronous spectral phase-encoded optical codedivision multiple-access (CDMA) system combined with timeencoding. The chip-level detection can enhance the tolerance of multiple access interference (MAI) because the channel collision does not occur as long as there is at least one weighted position without MAI. Moreover, the spectral-slice scheme can reduce the interference probability because the MAI with the different frequency has no adverse effects on the channel collision rate. As a result, these techniques mitigate channel collisions. We analyze the channel collision rate theoretically, and show that the proposed system can achieve a lower channel collision rate in comparison to both conventional systems with and without the time-encoding method.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.21-21
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• 2003

목적： 악성뇌종양 주변부위의 역동자기공명영상에서의 시간신호강도곡선 양상으로 종양의 성장 양상이나 예후를 판단할 수 있는지를 알고자 한다. 대상 및 방법： Anaplastic oligodendroglioma 3예, Anaplastic astrocytoma 1예, Glioblastoma multiforme 1예, Malignant ependymoma 2예, Medulloblastorna 1예로서, 총 8예의 종양절제전, 혹은 후의 잔류 종양을 대상으로 하였다. Routine MRI에 추가하여 종양부위에서 Turbo spin echo T1 강조 역동자기공명영상을 하였으며, Gd-DTPA 0.1 mmol/kg를 급속 주사 한 후, TR/TE, 350/15, slice thickness 6 mm, slice number 3, NEX 2회, scan time은 15 초로 하여 5 분 동안 20회 영상을 얻었다. 가시적으로 조영증강이 없는 종양의 주변부위나 수술경계부위에 관심영역을 그려서 시간신호강도곡선을 얻었으며, 첫 회 조영제 통과시의 peak 이후에 신호가 감소하는 경우를 Normal pattern으로, peak 이후에 신호가 계속 유지되거나 증가하는 경우를 Tumor pattern으로 하였으며, Normal pattern과 Tumor pattern을 보인 예들을 구분하여 종양의 재성장 상태와 환자의 생존 기간을 비교 관찰하였다.