• Korean Journal of Materials Research
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• v.26 no.8
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• pp.412-416
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• 2016

The electrical properties of Au/n-type Ge Schottky contacts with different contact areas were investigated using current-voltage (I-V) measurements. Analyses of the reverse bias current characteristics showed that the Poole-Frenkel effect became strong with decreasing contact area. The contribution of the perimeter current density to the total current density was found to increase with increasing reverse bias voltage. Fitting of the forward bias I-V characteristics by considering various transport models revealed that the tunneling current is dominant in the low forward bias region. The contributions of both the thermionic emission (TE) and the generation-recombination (GR) currents to the total current were similar regardless of the contact area, indicating that these currents mainly flow through the bulk region. In contrast, the contribution of the tunneling current to the total current increased with decreasing contact area. The largest $E_{00}$ value (related to tunneling probability) for the smallest contact area was associated with higher tunneling effect.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1931-1933
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• 1999

In this paper, the current and voltage properties on the gate oxide film due to the variation of thickness are studied. The specimen is used for n-ch power MOSFET. It is shows the leakage current and current density characteristics due to the applied electric field when the oxide thickness is each $600[\AA],\;800[\AA]$ and $1000[\AA]$, respectively. We known that the leakage current is a little higher when the voltage as reverse bias contrast with forward bias in poly gate is applied. In order to experiment for AC properties is measured for capacitance characteristics. It is confirmed that the value of input capacitance have been a lot of influenced on $SiO_2$ thickness contrast with the value of output capacitance.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.10
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• pp.33-40
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• 1993

A reflection type 16x8 S-SEED array from LP(Low Pressure)-MODVD-grown GaAs/AlGaAs extremely shallow quantum well(ESQW) structures, with 4% Al fraction, has been fabricated. Its intrinsic region consists of 50 pairs of alternating 100.angs. GaAs and 100.angs. $Al_{0.04}$Ga$_{0.96}$As layers. A multilayer reflector stack of $Al_{0.04}$/Ga$_{0.96}$ As(599$\AA$)/AlAs(723$\AA$) was incorporated for the reflection plane below the p-i-n structures. The device processing after the MOCVD growth includes the mesa etching, isolation etching, insulator deposition, p & n metallization, and AR(Anti-Reflection) coating. For switching characteristics of the S-SEED in the form of p-i-n ESQW diode, the maximum optical negative resistance was observed at 856nm. Reflectance measurements showed a change from 15.6% to 43.3% for +0.9V to -6V bias. The maximum contrast ration of the S-SEED array was 2.0 and all the 128 devices showed optical bistability with contrast ratios over 2.4 at 5V reverse bias.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.199-202
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• 2002

In general, the background light produced during the reset period deteriorates the dark room contrast ratio in AC PDP. In this paper, we propose a modified ramp reset pulse that can reduce the background light to imperceptible level. In the new reset waveform, the discharges between the scan and sustain electrodes are minimized by applying a positive bias voltage to the sustain electrode and only the weak discharges between the scan and address electrodes occur during the reset period. We adopted a MgO coated phosphor layer to get the same level of voltage margin in the new reset pulse scheme compared to that of the conventional ramp reset pulse one. As a result, the voltage margin is maintained at the same level and the dark room contrast ratio is improved dramatically.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.639-642
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• 2005

A new dual-slope ramp (DSR) reset waveform is proposed to improve the dark room contrast ratio in AC-PDPs. The proposed reset waveform has two different voltage slopes during a ramp-up period. The first voltage slope is lower than the conventional ramp voltage slope, causing a reduction in the background luminance, whereas the second voltage slope is higher than the conventional ramp voltage slope, causing an increase in the background luminance. Thus, a bias voltage is also applied during the second voltage-slope period to adjust the background luminance and address discharge characteristics. As a result, the proposed dual-slope reset waveform can lower the background luminance, thereby improving the high dark room contrast ratio of an AC-PDP without reducing the address voltage margin

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2361-2368
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• 2015

Objective: To evaluate the diagnostic accuracy of contrast-enhanced ultrasonography (CEUS) in differentiating between benign and malignant enlarged lymph nodes using meta-analysis. Materials and Methods: Pubmed, Embase, SCI and Cochrane databases were searched for studies (up to September 1, 2014) reporting the diagnostic performance of CEUS in discriminating between benign and malignant lymph nodes. Inclusion criteria were: prospective study; histopathology as the reference standard; and sufficient data to construct $2{\times}2$ contingency tables. Methodological quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Patient clinical characteristics, sensitivity and specificity were extracted. The summary receiver operating characteristic curve was used to examine the accuracy of CEUS. A meta-analysis was performed to evaluate the clinical utility in identification of benign and malignant lymph nodes. Sensitivity analysis was performed after omitting outliers identified in a bivariate boxplot and publication bias was assessed with Egger testing. Results: The pooled sensitivity, specificity and AUROC were 0.92 (95%CI, 0.85-0.96), 0.91 (95%CI, 0.82-0.95) and 0.97 (95%CI, 0.95-0.98), respectively. After omitting 3 outlier studies, heterogeneity decreased. Sensitivity analysis demonstrated no disproportionate influences of individual studies. Publication bias was not significant. Conclusions: CEUS is a promising diagnostic modality in differentiating between benign and malignant lymph nodes and can potentially reduce unnecessary fine-needle aspiration biopsies of benign nodes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.831-835
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• 2014

The relative concentration of surface and interfacial defects in hydrothermally grown ZnO nanostructures was investigated by a comparison of two samples having different growth temperatures via bias voltage sweep rate under laser illumination of 405 and 355 nm. The current of small ZnO nanostructures (growth temperature of $75^{\circ}C$) decreased when induced more slowly bias voltage sweep rate under the laser illumination. In contrast, the current of large ZnO nanostructures (growth temperature of $90^{\circ}C$) increased. This difference in currents indicates the relation of relative defects concentration between surface and interfacial defects of ZnO nanostructure. Our experimental approach has potential applicability in the analysis of influence on defects in ZnO devices.

• Atmosphere
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• v.18 no.4
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• pp.507-524
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• 2008

In this paper, future climate changes over East Asia($20^{\circ}{\sim}50^{\circ}N$, $100^{\circ}{\sim}150^{\circ}E$) are projected by anthropogenic forcing of greenhouse gases and aerosols using coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1, A1B and A2 scenarios. Before projection future climate, model performance is assessed by the $20^{th}$ Century (20C3M) experiment with bias, root Mean Square Error (RMSE), ratio of standard deviation, Taylor diagram analysis. The result of examination of the seasonal uncertainty of T2m and PCP shows that cold bias, lowered than that of observation, of T2m and wet bias, larger than that of observation, of PCP are found over East Asia. The largest wet bias is found in winter and the largest cold bias is found in summer. The RMSE of temperature in the annual mean increases and this trend happens in winter, too. That is, higher resolution model shows generally better performances in simulation T2m and PCP. Based on IPCC SRES scenarios, East Asia will experience warmer and wetter climate in the coming $21^{st}$ century. It is predict the T2m increase in East Asia is larger than global mean temperature. As the latitude goes high, the warming over the continents of East Asia showed much more increase than that over the ocean. An enhanced land-sea contrast is proposed as a possible mechanism of the intensified Asian summer monsoon. But, the inter-model variability in PCP changes is large.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2189-2195
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• 2007

In this paper, we propose a newly developed selective reset waveform of a ac PDP using the wide erase pulse technique with the control of address bias voltage. Although it is generally understood that the wide pulse erasing methode shows the narrow driving margin in an opposite discharge type ac PDP, we could obtain a moderate driving margin in a 3-electrode surface discharge type ac PDP. The obtained driving margin shows a strong dependency on the sustain voltage and the address bias voltage. The lower the sustain and the address bias voltage, the wider the driving margin. The pulse width of the proposed waveform is only $10{\mu}s$, which gives additional time to the sustain period, hence increases the brightness. The brightness and contrast ratio increase about 20% together comparing to the conventional ramp type selective reset waveform with the driving scheme of 10 subfield ADS method. The driving margin was measured with the line by line addressed pattern on the white test panel of 2inch diagonal size and the discharge gas was Ne+Xe4%, 400torr.

• Korean Journal of Materials Research
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• v.24 no.7
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• pp.344-350
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• 2014

Metal films (i.e., Ti, Al and SUH310S) were prepared in a magnetron sputtering apparatus, and their cross-sectional structures were investigated using scanning electron microscopy. The apparatus used consisted of a cylindrical metal target which was electrically grounded, and two anode rings attached to the top and to the bottom of the target. A wire was placed along the center-line of the cylindrical target to provide a substrate. When the electrical potential of the substrate was varied, the metal-film formation rate depended on both the discharge voltage and the electrical potential of the substrate. As we made the magnetic field stronger, the plasma which appeared near the target collected on the plasma wall surface and thereby decreased the bias current. The bias current on the conducting wire was different from that for cation collection. The bias current decreased because the collection of cations decreased when we increased the magnetic-coil current. When the substrate was electrically isolated, the films deposited showed a slightly coarse columnar structure with thin voids between adjacent columns. In contrast, in the case of the grounded substrate, the deposited film did not show any clear columns but instead, showed a densely-packed granular structure. No peeling region was observed between the film and substrate, indicating good adhesion.