• Title/Summary/Keyword: pmm

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Preparation of Polymer-modified Mortars with Recycled PET and Their Sound Absorption Characteristics (재활용 PET 를 이용한 고분자 몰타르의 제조 및 흡음 특성)

  • Hong, Byung-Pyo;Byun, Hong-Sik
    • Polymer(Korea)
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    • v.34 no.5
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    • pp.410-414
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    • 2010
  • Two different types of polymer-modified mortars(PMM) were prepared with recycled PET and fly-ash. One is rigid PMM and the other is flexible PMM which are based on the composition of recycled PET. Their mechanical properties including friction coefficient measurement and damping characteristics such as sound absorption were investigated and compared with the commercial PMM such as epoxy PMM and PET PMM. The result from mechanical properties indicated that the rigid PMM could be competitive with the commercial PET PMM. The measurement of sound absorption coefficient showed that both rigid PMM and flexible PMM had much better damping capacity than commercial PMM. However, the friction coefficient of rigid PMM revealed that it would be suitable for the use as floor material.

Identification and Characterization of the Vitro vulnificus Phosphomannomutase Gene

  • Lee, Jeong-Hyun;Park, Na-Young;Park, Soon-Jung;Choi, Sang-Ho
    • Journal of Microbiology and Biotechnology
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    • v.13 no.1
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    • pp.149-154
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    • 2003
  • Numerous virulence factors such as O antigen have been proposed to account for the fulminating and destructive nature of V. vulnificus infections. To better characterize the role of O antigen, a pmm gene encoding a phosphomannomutase was identified and cloned from V. vulnificus. The deduced amino acid sequence of the pmm was 42 to 71% similar to that reported from other Enterobacteriaceae. Functions of the pmm gene in virulence were assessed by the construction of an isogenic mutant, whose pmm gene was inactivated by allelic exchanges, and by evaluating its phenotype changes in vitro and in mice. The disruption of pmm resulted in a loss of more than 90% of phosphomannomutase, and reintroduction of recombinant pmm could complement the decrease of phosphomannomutase activity, indicating that the pmm gene encodes the phosphomannomutase of V. vulnificus. There was no difference in the $LD_50S$ of the wild-type and the pmm mutant in mice, but the $LD_50S$ observed by the mutant complemented with recombinant pmm were lower. Therefore, it appears that PMM is less important in the pathogenesis of V. vulnificus than would have been predicted by examining the effects of injecting purified LPS into animals, but it is not completely dispensable for virulence in mice.

Comparison of Hydrodynamic Coefficients obtained through Implementation of Diverse Methods in Square Tank

  • Kang, Seunghyun;Yoon, Hyeon Kyu
    • Journal of Navigation and Port Research
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    • v.38 no.1
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    • pp.11-18
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    • 2014
  • To confirm whether the square tank at Changwon National University (CWNU) can be used for estimation of maneuverability, planar motion mechanism (PMM) test and circular motion (CM) test were performed for various conditions. PMM test can be implemented using an XY carriage and a yaw table in the square tank. However, sometimes test section is insufficient for PMM test owing to low length-breadth ratio of the tank. In addition, the speed of a towing carriage is also quite limited. Therefore, it would be useful if PMM test could be effectively performed diagonally, by establishing coupled control logic to drive three servomotors. In addition, Froude number dependency on the estimated hydrodynamic coefficients was checked. Furthermore, CM tests, which cannot be completed in a conventional linear towing tank, were performed, and its results were compared with the results of PMM test. The results of the PMM tests in the diagonal direction were consistent with the results of the test performed in the direction parallel to the sidewall. However, the results of the CM test were greater than those of the PMM test. This tendency was also observed in the results published at Ulsan University.

Solution of TM Scattering Applying FGMM and PMM for Resistive Strip Grating Between a Grounded Double Dielectric Layer (접지된 2중 유전체층 사이의 저항띠 격자에 대해 FGMM과 PMM을 적용한 TM 산란 해)

  • Uei-Joong Yoon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.3
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    • pp.77-82
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    • 2023
  • In this paper, TM(tranverse magnetic) electromagnetic scattering problems for resitive strip grating between grounded double dielectric layers are analyzed by using the FGMM(fourier galerkin moment method) and PMM(point matching method) known as a numerical method of electromagnetic field. The boundary conditions are applied to obtain the unknown field coefficients, the resistive boundary condition is applied to analysis of resistive strip. Overall, when the unoform resistivity decreased, the magnitude of the current density induced in the resistive strip increased, and the reflected power also increased. Also, as the thickness and relative permittivity of the double dielectric layers increased, the overall reflected power increased. The numerical results obtained by using the numerical methods of FGMM and PMM to the structure proposed in this paper agree very well.

Estimation of Maneuvering Mathematical Model by System Identification Techniques (시스템 검증에 의한 조종수학 모형의 평가)

  • Lee, Ho-Young;Shin, Hyun-Kyoung
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4 s.35
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    • pp.118-123
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    • 1999
  • The mathematical model used in the simulation of ship's maneuvering contains the hydrodynamic coefficients, which are usually evaluated based on PMM model tests in the towing tank and used to predict ship's maneuvering performance when applied to the proto-type ship. The proper mathematical model has to be developed to predict ship's maneuvering motions with hydrodynamic coefficients very well. The mathematical model for PMM model tests is analyzed with identification program and the hydrodynamic coefficients and maneuvering motions by system identification we compared with those obtained directly from PMM model tests and sea trial. The mathematical model for PMM model tests was established and the magnitudes of ship's maneuvering coefficients were determined. When the identified values of coefficients were used to simulate the maneuvers, a very good agreement was obtained between the numerically simulated motion responses and those obtained from PMM model tests.

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A Study on Practical PMM Test Technique for Ship Maneuverability Using System Identification Method (선박의 조종성능 추정에 있어서 시스템식별법을 이용한 PMM 시험 기법에 대한 연구)

  • 이태일;권순홍
    • Journal of Ocean Engineering and Technology
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    • v.16 no.6
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    • pp.25-31
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    • 2002
  • A system identification method is introduced to increase the prediction accuracy of a ship's maneuverability in PMM test, analysis. To improve the accuracy of linear hydrodynamic coefficients, the analysis techniques of pure sway and yaw tests are developed, and confirmed. In the analysis of sway tests, accuracy to linear hydrodynamic coefficients depends on the frequency of sway motion. To obtain nonlinear hydrodynamic coefficients for large drift angles, a combined yaw test is introduced. Using this system identification method, runs of PMM test can be reduced while retaining sufficient accuracy, compared to the Fourier integration method. Through the comparisons with sea trial results and the Fourier integration method, the accuracy and efficiency of the newly proposed system identification method, based on least square method, has been validated.

Solution of TM Scattering Applying FGMM and PMM for Conductive Strip Grating Between a Grounded Double Dielectric Layers (접지된 2중 유전체층 사이의 도체띠 격자에 대해FGMM과 PMM을 적용한 TM 산란 해)

  • Uei-Joong Yoon
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.721-726
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    • 2023
  • In this paper, TM electromagnetic scattering problems for conductive strip grating between grounded double dielectric layers are analyzed by applying the FGMM(fourier galerkin moment method) and PMM(point matching method) known as a numerical method of electromagnetic field. The boundary conditions are applied to obtain the unknown field coefficients. In order to deal with the problem of grounded double dielectric layers, numerical calculation was performed only when the thickness and relative permittivity of the dielectric layers had the same value. As the thickness of the dielectric layer and the relative permittivity increased, the overall reflected power increased, and the minimum values of the reflected power shifted in the direction of increasing the strip width. The numerical results obtained by applying the numerical methods of FGMM and PMM to the structure proposed in this paper agree very well.

Expression and Cloning of the pmmC Gene Encoding Phosphomannomutase in Sphingomonas chungbukensis DJ77 (Sphingomonas chungbukensis DJ77 균주에서 Phosphomannomutase를 암호화하는 pmmC 유전자의 클로닝과 발현)

  • Kim Mi-Hye;Choi Jung-Do;Shin Malshick;Kim Young-Chang
    • Microbiology and Biotechnology Letters
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    • v.33 no.2
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    • pp.84-89
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    • 2005
  • Phosphomannomutase (PMM) is a key enzyme in prokaryotes and eukaryotes, which catalyzes the conversion of ${\alpha}$-D-mannose 6-phosphate to ${\alpha}$-D-mannose 1-phosphate. The latter is the substrate for the synthesis of GDP-mannose, which serves as the mannosyl donor for many metabolic pathways in the cells. We report here on the isolation of a gene from a genomic library of Sphingomonas chungbukensis DJ77, the pmmC gene encoding phosphomannomutase. The gene was cloned into E. coli expression vector, and the sequence was analyzed. The ribosomal binding site GGAAG lays 5 bp upstream of the ORF of 750 bp, which is initiated by ATG codon and terminated by TAG. The predicted sequence of the enzyme consists of 249 amino acids with a molecular mass of 27.4 kDa and showed $86.9\%$ similarity to that of eukaryotic phosphomannomutase after bioinformatical analyses with the conserved domain search of NCBI. The purified gene product revealed the activity of phosphomannomutase. In conclusion, we confirmed that pmmC gene encodes phosphomannomutase actually.

Piezoelectric PZT/Polymer Composite with 3-3 Connectivity (3-3 결합으로 이루어진 PZT/고분자 압전복합체)

  • 윤기현;염상덕
    • Journal of the Korean Ceramic Society
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    • v.25 no.2
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    • pp.125-130
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    • 1988
  • The characteristics of the PZT/PMM and PZT/Butadiene composites with 3 dimensional network structure have been investigated as a function of the PZT volume fraction. The dielectric constants of the PZT composites increased linearly as the PZT volume fraction increased. However, they are not significantly affected by the polymer compliance. The piezoelectric d33 coefficients of the PZT/Butadiene are largest than the PZT/PMM because of the high elastic compliance which promotes stress transfer. The values of the mechanical quality factor adn frequency factor of the PZT/PMM composite are slightly larger, while the planar coupling factor is smaller, than the PZT/Butadiene composite. These results are due to strong interaction and mechanical coupling between PZT and PMM.

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Attachment distribution of pectoral muscle origins identified in dual-plane breast implant insertion

  • Nam, Su Bong;Song, Kyung Ho;Seo, Jung Yeol;Choi, June Seok;Park, Tae Seo;Lee, Jae Woo;Kim, Ju Hyung;Kim, Min Wook;Kim, Hyun Yeol;Jung, Yun Ju;Kim, Choongrak
    • Archives of Plastic Surgery
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    • v.47 no.2
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    • pp.160-164
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    • 2020
  • Background Implant-based dual-plane augmentation mammoplasty requires accurate separation of the pectoralis major muscle (PMM) at its origins. The authors identified the PMM origins during breast reconstruction surgery with the goal of providing additional information on subpectoral implant insertion for reconstructive or aesthetic purposes. Methods This study was conducted on 67 patients who underwent breast reconstruction surgery at the breast center of our hospital between November 2016 and June 2018. In total, 34 left and 39 right hemithoraces were examined. The left and right hemithoraces were each divided into 15 zones to determine the percentage of PMM attachments in each zone. The distribution of PMM origins in each zone was examined to identify any statistically significant differences. Results There were no statistically significant differences in the origins of the PMM between the right and left hemithoraces. The percentage of attachments increased moving from the fourth to the sixth rib and from the lateral to the medial aspect. Conclusions The anatomical findings of this study could be used as a reference for accurate dissection of the origins of the PMM for the preparation of the subpectoral pocket for subpectoral implant placement.