• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.169-174
• /
• 1986

This thesis investigates the scanning time ; one of the most important performance index of Programmable Controller(PC). The multiprocessor architecture of the large PC considered in this thesis are classified as architecture 1 and architecture 2 by the bus control methods. The queuing model of each architecture is developed. Form the analysis it is observed that in the case of the number of processors less than 3 the best architecture of the large PC is the architecture 2 and in the case of the number of processors greater than 2 the best architecture of the large PC is the architecture 1.

• Journal of the Ergonomics Society of Korea
• /
• v.17 no.2
• /
• pp.97-104
• /
• 1998

This study reviews usability of PC communication softwares with different dialogue types of user interface. Usability test was conducted to evaluate usability of 3 PC communition softwares which are currently utilized in Korea. Learnability was adopted as an index of usability evaluation, so learning time, testing time and scores were measured as dependent variables. It is suggested that softwares with mixing dialogue type(menu, icon, command) which were implemented in window systems environment were not superior to that with command dialogue type.

• Polymer(Korea)
• /
• v.31 no.5
• /
• pp.399-403
• /
• 2007

Trans-esterification behavior of polycarbonate/poly(butylene terephthalate) (PC/PBT) blends was investigated during the melt mixing process. Rheological and fracture behaviors, and fracture morphology were also investigated as a function of PC/PBT blend ratio. Based on FT-IR and $^1H-NMR$ results, a trans-esterification reaction was confirmed to occur between PC and PBT during the melt mixing process. The melt index(MI) decreased with increased PC content, indicating the higher flow resistance of PC. The storage and loss moduli were increased by increasing the PC loading, and the PC/PBT blends were rheologically incompatible based on the Cole-Cole plot. The tensile property increased linearly with the increased PC content. However, the impact strength increased until 50 wt% of PC loading, notably around $30{\sim}40wt%$, and then was levelled off at 50 wt%. Rough ridges were formed on the impact fracture surfaces above the 40 wt% of PC content, supporting the observed higher impact strength in this range.

• The Journal of Korean Medicine
• /
• v.38 no.4
• /
• pp.41-54
• /
• 2017

Objectives: The purpose of this study is to investigate the effects of Sa-am acupuncture with Pericardium jung-gyuck (SA-acu-PC) and Triple Energizer jung-gyuck (SA-acu-TE) on the radial pulse in healthy human subjects. Methods: Sixty healthy subjects participated in this study and divided into three groups randomly: Control group(C), Pericardium jung-gyuck group(PC), Triple Energizer jung-gyuck group(TE). Radial pulse was measured by 3 dimensional pulse imaging system (DMP-3000) before, right after, 30 minutes after, and 60 minutes after acupuncture. Results: 1. The changes observed in periodic parameters are considered as the common effects of both SA-acu-TE and SA-acu-PC. SA-acu-TE was more effective than SA-acu-PC in these effects. 2. The effects of SA-acu-PC appeared in the pulse amplitude, pulse area, and pulse power volume mainly at the left chon position, and 3. The effects of SA-acu-TE appeared in the radial augmentation index and main peak angle mainly at the right gwan position. Conclusions: The effects of SA-acu-PC and SA-acu-TE can be observed in the radial pulse. The increases in pulse amplitude, pulse area, and pulse power volume at the left chon may imply the effects of SA-acu-PC. And the decrease in the pulse power volume, the increases in radial augmentation index and main peak angle may imply the effects of SA-acu-TE.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.5
• /
• pp.1-11
• /
• 1993

Precast/Prestressed concrete segmental bridges with moderate range of span length normally have a constant section height for economic segment manufacturing. Inside sectional dimension is often controlled for design of non-prismatic section between supports when variable stiffness is required. It is usual, in the preliminary design stage, to adopt trial bridge sections by past experience or by approximately estimated member forces. Three bridge models of different member stiffness have been selected to investigate flexural stiffness effects on member forces for preliminary design stage. The selected bridge stiffness has been determined by the flexibility index from review of the practically usable sections.

• Macromolecular Research
• /
• v.17 no.12
• /
• pp.1021-1024
• /
• 2009

We successfully prepared high-flow polycarbonate (PC) by blending commercial PC with a low molecular weight PC oligomer. The oligomer was synthesized by the addition of a large quantity of mono functional phenol groups, and the chain end group was reacted with p-tertiary butyl phenol (PTBP) to block the reactivity. The viscosity average molecular weight ($M_v$) for the oligomer was about 4,000-5,000 g/mol, compared to ~19,000 g/mol for the PC blend obtained by blending 10 wt% of the prepared oligomer with the commercial grade PC ($M_v$ of 21,000 g/mol). The blended PC had a melt flow index of 45, which is 2.5 times higher, and a processing temperature that was $20^{\circ}C$ lower, than that of commercial grade PC having a similar $M_v$.

• Composites Research
• /
• v.34 no.1
• /
• pp.1-7
• /
• 2021

Fiber-reinforced thermoplastic composites are applied to transport industries to lightweight of body, and applications will be expanded gradually. In this study, the impregnation and mechanical properties of continuous glass fiber (GF) reinforced polycarbonate (PC) composites were evaluated with different molecular weights of PC. The continuous GF reinforced PC composite were prepared by using GF fabric and PC film via continuous compression molding method. The melting flow index and tensile strength of PC matrix were evaluated with different molecular weights. Mechanical properties (tensile, flexural, and compressive) and pore rate of GF/PC composite were evaluated with different molecular weights of PC. The fracture behavior was analyzed to fracture surface of GF/PC composite using FE-SEM images. As these results, it was condition of representing the best mechanical property that the GF/PC composite was prepared by using PC of 20,000 g/mol as matrix.

• Polymer(Korea)
• /
• v.29 no.5
• /
• pp.457-462
• /
• 2005

Polyurethane foams (PUFs) were prepared from polymeric 4,4'-diphenylmethane diisocyanate (PMDI), mixed polyol with OH value of 480, silicone surfactant, three catalysts, and hydrofluorocarbon(HFC) as blowing agent. Balance (PC-8), gelling (33LV), and trimerization (TMR-2) catalysts were used. The effect of the catalysts on the physical properties of PUF with increase of isocyanate (NCO) index and aging time was investigated. The cell size of the PUF with PC-8 and 33LV slightly increased with an increase in NCO index from 100 to 170 but compressive strength did not change significantly. In case of trimerization catalyst, the compressive strength of PUF increased from 8.75 to 1$10.5 kg_f/cm^2$ and the cell size decreased with an increase in NCO index. The compressive strength of the PUF with 33LV increased from 9.21 to $10.15 kg_f/cm^2$ with an increase in aging time. However, there was no detectable change in the compressive strength of PUF with TMR-2. A possible interpretation of the results includes an additional cross-link reaction of non-reacted MDI and FTIR spectrum illustrated the change of NCO peak.

• The Journal of Internal Korean Medicine
• /
• v.45 no.4
• /
• pp.744-759
• /
• 2024

Objectives: This study reviewed randomized controlled trials (RCTs) investigating the effects of Neiguan (PC6) stimulation on blood pressure and suggests a better research process. Methods: We searched for RCTs for effects of Neiguan (PC6) stimulations on blood pressure published until July 2024 using six databases (PubMed, Oriental Medicine Advanced Searching Integrated System (OASIS), Korea Citation Index (KCI), Research Information Service System (RISS), Korean Studies Information Service System (KISS), and Science ON). In total, eight RCTs that met all the inclusion criteria were selected. Results: All the selected studies showed significant effects of Neiguan (PC6) stimulation on blood pressure. In most studies, Neiguan (PC6) stimulation was effective in stabilizing blood pressure and improving various indicators related to blood pressure. Conclusion: Neiguan (PC6) stimulation is an effective treatment for stabilizing blood pressure. However, the selected RCTs were short-term studies and had small number of subjects; so, long-term and large-scale studies are needed.

• Journal of the Korean earth science society
• /
• v.35 no.4
• /
• pp.249-258
• /
• 2014

Despite the greenhouse gases like carbon dioxide have steadily increased in atmosphere, the overall trend of the global average surface air temperature has stalled during the last decade (2002-present). This phenomenon is often called hiatus or warming pause, which is challenging the prevailing view that anthropogenic forcing causes warming environment. Our study characterized the hiatus by analyzing the HadGEM2-AO (95 yrs) simulation data based on RCP8.5 scenario. The PC2 time series from the EOF of the zonal mean vertical ocean temperature has been defined as the index that represents the warming pause. The relationship between the hiatus, ENSO and the changes in climate system are identified by utilizing the newly defined PC2. Since the La Nina index (defined as the negative of NINO3 index) leads PC2 by about 11 months, it may be possible that the La Nina causes the warming to be interrupted. We also show that the cooling of the climate system closed tied to the heat penetration into the deep ocean, indicating the weakening the warming rate is due to the oceanic heat uptake. Finally, the global warming hiatus is characterized by the anomalous warming in Arctic region as well as the intensification of the trade wind in the equatorial Pacific.