• Journal of the Korean Vacuum Society
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• v.14 no.1
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• pp.29-34
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• 2005

The degradation of the SiGe hetero-junction bipolar transistor(HBT) properties in SiGe BiCMOS process was investigated in this paper. The SiGe HBT prepaired by SiGe BiCMOS process, unlike the conventional one, showed the degraded DC characteristics such as the decreased Early voltage, the decreased collector-emitter breakdown voltage, and the highly increased base leakage current. Also, the cutoff frequency(f/sub T/) and the maximum oscillation frequency(f/sub max/) representing the AC characteristics are reduced to below 50%. These deteriorations are originated from the change of the locations of emitter-base and collector-base junctions, which is induced by the variation of the doping profile of boron in the SiGe base due to the high-temperature source-drain annealing. In the result, the junctions pushed out of SiGe region caused the parastic barrier formation and the current gain decrease on the SiGe HBT device.

• Membrane Journal
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• v.22 no.3
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• pp.216-223
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• 2012

The effect of water back-flushing period (FT) was investigated in hybrid process of carbon fiber microfiltration membrane and photocatalyst for advanced drinking water treatment in this study, and compared with the previous study using alumina ultrafiltration membrane. The FT was changed in the range of 2~10 min with fixed 10 sec of BT. Then, the FT effects on resistance of membrane fouling ($R_f$), permeate flux (J) and total permeate volume ($V_T$) were observed during total filtration time of 180 min. As decreasing FT, $R_f$ decreased and J increased, which was same with the previous result using alumina ultrafiltration membrane. The treatment efficiency of turbidity was high beyond 99.2%, and the effect of FT was not shown on treatment efficiency of turbidity, which was different with the previous result. The treatment efficiency of organic matters was the lowest value of 65.6% at NBF, and it increased as decreasing FT, which was different with the previous result, too. The reason was that the membrane fouling phenomena could show a different mechanism depending on ceramic membrane materials.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.194-199
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• 1997

When voltage or current gets out of the magnetic sensor as it is, we have often faced the problems such as introduction of noise and loss of voltage. In order to reduce these problems, a 2 drain MAGFET operating in the saturation region and fabricated by CMOS process, the system of I/V converter, VCO with operational amplifier, and V/F conversion circuits with Schmitt Trigger are designed and fabricated in one package. The absolute sensitivity of magnetic sensor shows 1.9 V/T and the product sensitivity is $3.2{\times}10^{4}\;V/A{\cdot}T$. The characteristic of V/F conversion is very stabilized and has the value of 190 kHz/T.

• Smart Media Journal
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• v.5 no.4
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• pp.9-17
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• 2016

Over the next 20 years it will begin the exodus from the Internet and smart phones to the Internet of Things. The heart of IoT gives new utility and value with connectivity among things around people to the human. In future, Industrial environment will be intimately connect all among machines and machines or factories and factories in all processing, and by digitizing of all goods and production life-cycle, which is a combination of virtual world and real world, the digital factory will become reality eventually. The proposed IoT or IIoT based Download OTA (Over-the-Air) provides a flexible mechanism for downloading Media objects of any type and size from a network. Moreover, proposed IoT based DLOTA provides a part of security by lightweight encryption, OTP, and CapBAC technique.

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.332-340
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• 2019

Due to the change in lifestyle, new sensible materials for sportswear and outdoor are needed. This study is conducted in order to obtain the data for sensible materials through nylon twist process. 1-step nylon twisting machine was used to set the optimum twist process. DSC measurements of twisted nylon yarn showed crystallization temperatures around 170℃ and melting temperatures around 220℃. Nylon 40D/13F DTY and Nylon 50D/48F DTY showed optimal results at 160℃, 1,500 T/M(Turns per meter), and Nylon 70D/68F DTY at 160℃, 1,200 T/M(Turns per meter) after 1-step twist process. Also, Nylon 40D/13F DTY was confirmed to have inter-layer property deviation of ±5 percent.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7648-7655
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• 2015

Nursing service quality can vary depending on the work attitude and behavior of nurses. Nursing attitude and behavior that can be described as voluntary and proactive organizational citizenship behavior(OCB). OCB affects the work performance of nurses in clinical practice is very important and organizational justice is an important influencing factors of OCB. The purpose of this study was to determine the influential factors of organizational justice on OCB of nurses. The descriptive-correlational method was applied. The study was carried out less than a 500-bed hospital. Participants of the study included 230 nurses working in secondary hospitals. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient and multiple regression with the 18.0 SPSS/Window program. Considering the components of organizational justice, there was a significant positive correlation(r=.172~.540, p=.000) between OCB and distributive, procedural and interactional justice. Also, Total organizational justice explained 29.1% of total OCB with influencing factor (${\beta}$=.540) and was statistically significant(F=93.777, p=.000). The influencing factors to OCB were distributive justice(${\beta}$=.283) and interactional justice(${\beta}$=.249) except procedural justice. The findings suggest that strategies of nursing management are needed to focus on distributive justice for compensation and interactional justice for social relationship in order to induce nurses' organizational citizenship behavior.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.91-98
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• 2013

Magnetic sensor chip for measuring bio-magnetism is implemented in $0.18{\mu}m$ CMOS technology. The magnetic sensor chip consists of a small-sized high inductance coil sensor and an instrumentation amplifier (IA). High inductance coil sensor with suitable sensitivity and bandwidth for measurement of bio-magnetic signal is designed using electromagnetic field simulation. Low gm operational transconductance amplifier (OTA) using transconductance reduction techniques is designed for on-chip solution. Output signal sensitivity of magnetic sensor chip is $3.25fT/{\mu}V$ and reference noise of 21.1fT/${\surd}$Hz. Proposed IA is designed along with band pass filters(BPF) to reduce magnetic signal noise by using current feedback techniques. Proposed IA achieves a common mode rejection ratio of 117.5dB while the input noise referred is kept below $0.87{\mu}V$.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.557-564
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• 2019

The purpose of this study was to examine the influencing factors of job engagement among Korean police officers. This was the secondary analysis of data from the 5th Korean Working Conditions Survey (KWCS). The study subjects included 185 Korean police officers. Collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation and multiple regression with IBM SPSS Statistics 24.0 program. Job insecurity (${\beta}=-.34$, p<.001), job reward (${\beta}=.39$, p<.001), subjective health status (${\beta}=.22$, p<.001), and organizational justice (${\beta}=.20$, p=.002) were significant influencing factors on job engagement, explaining 59.3% of the variance (F=34.26, p<.001). Effective and systematic strategies to improve Korean police officers' job engagement should focus on job reward, job insecurity, subjective health status, and organizational justice. The results of this study can be utilized as base data to improve Korean police officers' job engagement.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.257-262
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• 2013

The fluorine-containing waste water tends to show a higher removal efficiency through the coagulative precipitation process with calcium. However the tetrafluoroborate produced from the etching process is difficult to remaval due to it's low reactivity with calcium. The objective of this study is improving the efficiency of fluoride ion removal in tetrafluoroborate through decomposing. Research on tetrafluoroborate decomposition depending on reaction pH, temperature, and aluminum dosage were conducted, using a laboratory-scale reactor. The result shows that the reaction of tetrafluoroborate with aluminum is faster with lower pH, higher water temperature, and higher Al/T-F (Aluminum/Total Fluoride) mole ratio. It is found that there was no big change in concentration after over 120 minutes of reaction. This study is to be able to improve the efficiency of tetrafluoroborate and fluoride wastewater treatment by using aluminum.

• Membrane Journal
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• v.21 no.2
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• pp.127-140
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• 2011

The effects of $TiO_2$ photocatalyst coating bead concentration, water-back-flushing period (FT), and back-flushing time (BT) were investigated in hybrid process of ceramic ultrafiltration and photocatalyst for advanced drinking water treatment in this study. Photocatalyst coating bead concentration was changed in the range of 10~40 g/L, FT in 2~10 min and BT in 6~30 sec. Then, we observed the effects on resistance of membrane fouling $(R_f)$, permeate flux (J) and total permeate volume $(V_{\Upsilon})$ during total filtration time of 180 min. As decreasing photocatalyst coating bead concentration, $R_f$ increased and J decreased. $V_{\Upsilon}$ was the highest value of 8.85 L at 40 g/L of photocatalyst coating bead concentration. At FT change experiment, $R_f$ decreased and J increased as decreasing FT. Then $R_f$ decreased and J increased according to increasing BT at BT change experiment. Because at NBF (no back-flushing) dramatic membrane fouling reduced membrane pore size, turbid and dissolved organic matters ($UV_{254}$ absorbance) could be removed efficiently. Therefore, treatment efficiencies of turbidity and dissolved organic matters were the highest at NBF. Then by cleaning effect of photocatalyst coating bead, the treatment efficiencies of turbidity and dissolved organic matters increased as decreasing FT and increasing BT.