• Title/Summary/Keyword: PC/A ratio

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Depolymerization of Polycarbonate Waste by Ethylene Glycol (에틸렌글리콜을 이용한 폐폴리카보네이트 해중합 특성)

  • Kim, Dongpil;Kim, Bo-kyung;Cho, Youngmin;Han, Myungwan;Kim, Beom-Sik
    • Korean Chemical Engineering Research
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    • v.46 no.5
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    • pp.875-879
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    • 2008
  • A method for the depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The effect of operation variables such as reaction time, reaction temperature, EG/PC weight ratio and the kinetic of glycolysis were studied. It was found that the polymerization reaction has two different activation energies depending on the reaction temperature. A drop in activation energy with temperature indicates that the reaction mechanism has shifted from one of a succession of elementary steps to another in the series. The maximum yield of BPA of 95.6% was achieved at reaction temperature $220^{\circ}C$ for 85min with EG/PC weight ratio 4.

Spatiotemporal Clusters and Trends of Pneumocystis Pneumonia in Korea

  • Kim, Hwa Sun;Nam, Ho-Woo;Ahn, Hye-Jin;Lee, Sang Haak;Kim, Yeong Hoon
    • Parasites, Hosts and Diseases
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    • v.60 no.5
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    • pp.327-338
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    • 2022
  • This study determined the recent status and trend of Pneumocystis jirovecii pneumonia (PcP) in the non-human immunodeficiency virus (HIV) (non-HIV-PcP) and HIV (HIV-PcP) infected populations using data from the Health Insurance Review & Assessment Service (HIRA) and the Korea Disease Control and Prevention Agency (KDCA). SaTScan and Join-point were used for statistical analyses. Non-HIV-PcP cases showed an upward trend during the study period from 2010 to 2021, with the largest number in 2021 (551 cases). The upward trend was similar until 2020 after adjusting for the population. Seoul had the highest number of cases (1,597) in the non-HIV-PcP group, which was the same after adjusting for the population (162 cases/1,000,000). It was followed by Jeju-do (89 cases/1,000,000). The most likely cluster (MLC) for the non-HIV-PCP group was Seoul (Relative Risk (RR)=4.59, Log Likelihood Ratio (LLR)=825.531), followed by Jeju-do (RR=1.59, LLR=5.431). An upward trend was observed among the non-HIV-PcP group in the Jeju-do/Jeollanam-do/Jeollabuk-do/Gyeongsangnam-do/Busan/Daejeon/Daegu/Ulsan joint cluster (29.02%, LLR=11.638, P<0.001) located in the southern part of Korea. Both women and men in the non-HIV groups showed an overall upward trend of PcP during the study period. Men in the 60-69 age group had the highest annual percentage change (APC 41.8) during 2014-2019. In contrast, the HIV groups showed a falling trend of PcP recently. Men in the 60-69 age group had the most decrease (APC -17.6) during 2018-2021. This study provides an analytic basis for health measures and a nationwide epidemiological surveillance system for the management of PcP.

High-resolution Shallow Marine Seismic Survey by Using a Multi-channel Seismic System (다중채널을 이용한 천해저 고해상 해양 탄성파탐사)

  • Kim, Hyun-Do;Kim, Jin-Hoo
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.757-763
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    • 2005
  • A multi-channel seismic system has been developed and applied for bedrock mapping in near shore environment. The system is composed of an analog signal processor and an A/D converter installed on the computer, and a streamer with the group interval of 5 meters. The system is accomplished with a data acquisition program which controls the system and a data processing software. With the PC-based shallow marine seismic survey system high-resolution 2-D marine seismic profiles which have high S/N ratios can be obtained after appropriate data processing.

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Analysis of the Factors Influencing the Mesopore Ratio on the Soil Surface to Investigate the Site Factors in a Forest Stand (III) - With a Special Reference to Mixed Stands - (산림(山林)의 입지환경인자(立地環境因子)가 표층토양(表層土壤)의 조공극률(組孔隙率)에 미치는 영향인자(影響因子) 분석(分析) (III) - 혼효임(混淆林)을 중심(中心)으로 -)

  • Park, Jae Hyeon;Jeong, Yongho;Kim, Kyong Ha;Youn, Ho Joong
    • Journal of Korean Society of Forest Science
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    • v.90 no.6
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    • pp.683-691
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    • 2001
  • This study aimed to clarify the influencing factors of the mesopore ratio on a pore geometry of surface soil in mixed stands as an index of the water retention capacity. Twenty four factors including site conditions and soil properties were analyzed by spss/pc+ for the data collected from during March to October of 1995. The factors influencing the mesopore ratio(pF2.7) on the surface soil were as follows; mesopore ratio(pF2.7) on the B horizon soil, under vegetation coverage, organic matter contents of surface soil and F layer depth. And influencing factor on the ratio of mesopore in the soil surface was correlated with surface soil hardness and depth of 10cm soil hardness shows high negative significance. Also, multiple regression equations for mesopore ratio of the mesopore ratio of B horizon soil and organic matter contents shows high significance($R^2$; 0.84).

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An Experimental Study on Engineering Properties of Self-healing Mortar according to PCC(Powder Compacted Capsule) Size and Mixing Ratio (PCC(Powder Compacted Capsule) 크기 및 혼입율에 따른 자기치유 모르타르의 공학적 특성에 관한 실험적 연구)

  • Jae-In, Lee;Chae-Young, Kim;Se-Jin, Choi
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.10 no.4
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    • pp.514-522
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    • 2022
  • In this study, as part of a study to improve the self-healing performance of concrete structures by applying self-healing capsules made of cementitious materials to cement composite materials, the engineering characteristics of mortars according to PCC(Powder Compacted Capsule) size and mixing ratio were compared and analyzed. For this, fluidity, compressive strength, reload test, carbonation, ultrasonic velocity, and water permeability characteristics were measured according to PCC size and mixing ratio of mortar. As a result of the measurement, the fluidity and compressive strength increased as the mixing ratio of PCC increased, and in the case of the load reload test, the healing ratio increased as the mixing ratio of PCC increased in the 03PC formulation. In the case of water permeability test, it was found that when PCC was used, the reduction ratio of water flow was up to 35 % higher than that of Plain, and when PCC with a size of 0.3 to 0.6 mm was mixed with 15 %, it was found to be effective in improving the crack healing ratio of the mortar.

Responses in growth performance and nutrient digestibility to a multi-protease supplementation in amino acid-deficient broiler diets

  • Cho, Hyun Min;Hong, Jun Sun;Kim, Yu Bin;Nawarathne, Shan Randima;Choi, Inchul;Yi, Young-Joo;Wu, Di;Lee, Hans;Han, Seung Eun;Nam, Ki Taeg;Seoung, Eun Il;Heo, Jung Min
    • Journal of Animal Science and Technology
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    • v.62 no.6
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    • pp.840-853
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    • 2020
  • The present study was conducted to investigate the effect of a multi-protease on production indicators of broiler chickens fed a crude protein and amino acid deficient-diets for 35 days immediately after hatch. A total of 448 one-day-old Ross 308 male broiler chicks were allocated in a completely randomized design into one of eight dietary treatments (positive control [PC], negative control [NC: minus 0.5% from PC, and minus 2% of lysine, methionine, threonine and methionine plus cysteine], extreme negative control [ENC: minus 1% from PC, minus 4% of lysine, methionine, threonine and methionine plus cysteine], and plus multi-protease 150 or 300 g per ton [e. g., PC-150]; PC, PC-150, NC, NC-150, NC-300, ENC, ENC-150, ENC-300) to give eight replicates with seven birds in a battery cage. Body weight, average daily gain, average daily feed intake, feed conversion ratio, and mortality were measured every week. Carcass traits, proximate analysis of breast meat, and ileum digestibility were analyzed on day 21 and 35. Feeding a multi-protease (i.e., more than 150 g/ton) for 35 days immediately after hatching improved feed efficiency and ileum digestibility (i.e., dry matter, crude protein, and energy) compared to their counterparts (i.e., diets without multi-protease: PC, NC, and ENC). In conclusion, our results indicated that broiler chickens fed nutrients deficient-diet (i.e., crude protein and amino acids) supplemented a multi-protease had an ability to compensate and (or) improve their growth performance commensurate with increased ileal digestibility for 35 days immediately after hatch.

Characterization of Recycled Coarse Aggregate (RCA) via a Surface Coating Method

  • Ryou, J.S.;Lee, Y.S.
    • International Journal of Concrete Structures and Materials
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    • v.8 no.2
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    • pp.165-172
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    • 2014
  • Recycled coarse aggregate (RCA) made from waste concrete is not a suitable structural material as it has high absorption of cement mortar, which adheres on the aggregate surface and on the tiny cracks thereon. Therefore, when using RCA made from waste concrete, much water must be added with the concrete, and slump loss occurs when transporting. Hence, its workability is significantly worse than that of other materials. In this study, surface of RCA was coated with water-soluble polycarboxylate (PC) dispersant so that its characteristics improved. Each possibility was evaluated: whether its slump loss can be controlled, by measuring its workability based on the elapsed time; and whether it can be used as a structural material, by measuring its strength. Moreover, the carbonation due to cement mortar adhesion was measured through a carbonation test. As a result, RCA coated with PC dispersant was found to be better than crushed coarse aggregate and RCA when the physical properties of the fresh concrete and the mechanical, durability of the hardened concrete were tested.

Realization of Plasmonic Adaptive Coupler using Curved Multimode Interference Waveguide (곡면형 다중모드 간섭 도파로를 사용한 플라즈마 적응 결합기의 구현)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.2
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    • pp.165-170
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    • 2016
  • Nano-scale power splitter based on curved plasmonic waveguides are designed by utilizing the multimode interference (MMI) coupler. To analyze easily the adaptive properties of plasmonic curverd multimode interference coupler(PC-MMIC), the curved form transforms equivalently into a planar form by using conformal transformation method. Also, effective dielectric method and longitudinal modal transmission-line theory are used for simulating the light propagation and optimizing the structural parameters at 3-D guiding geometry. The designed $2{\times}2$ PC-MMIC does not work well for quasi-TM mode case due to the bending structure, and it does not exist 3dB coupling property, in which the power splitting ratio is 50%:50%, for quasi-TE mode case. Further, the coupling efficiency is better when the signal is incident at channel with large curvature radius than small curvature radius.

PSPICE Modeling of Commercial ICs for Switch-Mode Power Supply (SMPS) Design and Simulation

  • Yi, Yun-Jae;Yu, Yun-Seop
    • Journal of information and communication convergence engineering
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    • v.9 no.1
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    • pp.74-77
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    • 2011
  • PSPICE modeling of a commercial LED driver IC (TOP245P) and PC817A optocoupler is proposed for the switch-mode power supply (SMPS) (applicable to LED driver) design and simulation. An analog behavioral model of the TOP245P IC including the shunt regulator, under-voltage(UV) detection, over-voltage(OV) shut-down and SR flip-flop is developed by using PSPICE. The empirical equation of PC817A current transfer ratio (CTR) is fitted from the datasheet of PC817A. Two types of SMPSs are simulated with the averaged-model and switching-model. The simulation results by the proposed PSPICE models are in good agreement with those in the data sheet and an experimental data.

A study on Linear Pattern Fabrication of Plate-type PC (PC소재의 선형 패턴 제작에 관한 연구)

  • Joung, Y.N.;Lee, E.K.;Kang, C.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.277-280
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    • 2008
  • Recently, a demand of nano/micro patterned polymer for display or biochip has been rising. Then many studies have been carried out. Nano/micro-embossing is a deformation process where the workpiece materials is heated to permit easier material flow and then forced over a planar patterned tool. In this work, the hot-emboss process is performed with different forming conditions; forming temperature, load, press hold time, to get the proper condition for linear pattern fabrication on plated-type polymers (PC). Replicated pattern depth increases in proportion to the forming temperature, load and time. Reduction of the workpiece thickness increases according to press hold time. In process of time, reduction ratio of workpiece thickness decreases because of surface area increment of the workpiece and pressure decline on it.

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