• 제목/요약/키워드: helix

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Development of a Optimal Design Program for the Helical Gear on Vehicle Transmission (자동차 트랜스미션용 헬리컬 기어의 최적 설계 프로그램 개발)

  • Shim, Jae-Yong;Kwak, Jae-Seob;Song, Ji-Bok
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.11
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    • pp.88-93
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    • 2000
  • Recently the gear design focuses on the optimal design to extract the design factors from the vehicle transmission that is required to equip the powerful, speedy and silent characteristics. In this study, we had determined modules($m_n$) and face widths (b) to sustain strengths of contact and bending. The pressure angle ($\alpha$) and the helix angle ($\beta$) also had been obtained from the constraint of a contact ratio ($\varepsilon) on helical gears. Through the optimal design algorithm suggested in this study, the design factors were calculated on vehicle transmission gears and those determined factors were able to firm a suitability of the design.

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Derivation of Effective Material Properties of Reinforced Braid Layer Using Detailed 3-D Finite Element Model (상세 유한요소 모델을 이용한 섬유 보강사의 등가물성 유도)

  • Song, Jeong-In;Cho, Jin-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1752-1759
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    • 2004
  • Reinforced braid layer (RBL) in automobile power steering hose plays an important role in power steering system. When the working oil is applied to the power steering hose, RBL suppresses rubber hose deformation from internal pressure and heat expansion. RBL is woven textile composites having a double-row structure of nylon cords twisted with the specific helix angle. In this paper, effective material properties of RBL are estimated using a detailed 3-D finite element model considering its complicated geometry. Numerical experiments based on a superposition method are carried out to simulate uniaxial tensile loading condition.

Establishing National Science and Technology Park in Pakistan

  • Hashmi, Amer;Shah, Ali
    • World Technopolis Review
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    • v.1 no.4
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    • pp.264-275
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    • 2013
  • This paper presents the concept of the National Science and Technology Park (NSTP) in Islamabad, Pakistan. Keeping in line with Karl Popper's Piecemeal Social Engineering theory, a critical-pragmatic approach is adopted in shedding light on the strategic thrusts and expected outcomes of this knowledge-driven, entrepreneurially-spirited, multi-industry project. Based on Triple-Helix perspectives, we investigate the role of the National University of Sciences and Technology, Islamabad in efforts aimed at developing NSTP as an intermediary hybrid organization that enhances industry-academia-government linkages, with the potential to serve as an engine for regional and national economic growth and competitiveness.

Cutting Performance of Tool in work of CFRP Hole (CFRP 구멍가공 시 공구의 절삭성능에 관한 연구)

  • Shin, H.G.;Kang, G.W.;Kim, Y.C.;Moon, J.S.;Whang, S.K.
    • Journal of the Korean Society of Mechanical Technology
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    • v.20 no.6
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    • pp.941-946
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    • 2018
  • Currently, due to the development of technology, the industry is proceeding with the development of advanced materials with high performance such as light weight, heat resistance and electric conductivity. Carbon Fiber Reinforced Plastics (CFRP) is an excellent material with high heat resistance, high strength and thermal shock resistance. In order to obtain excellent hole shape in CFRP drilling, we compared the modified drill shape and the conventional carbide drill. On the other hand, we determine the proper helix angle by observing the CFRP surface according to the helix angle at the trimming of the end mill proceeding after the hole machining.

Crystal Structure of the Pneumococcal Vancomycin-Resistance Response Regulator DNA-Binding Domain

  • Park, Sang-Sang;Lee, Sangho;Rhee, Dong-Kwon
    • Molecules and Cells
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    • v.44 no.3
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    • pp.179-185
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    • 2021
  • Vancomycin response regulator (VncR) is a pneumococcal response regulator of the VncRS two-component signal transduction system (TCS) of Streptococcus pneumoniae. VncRS regulates bacterial autolysis and vancomycin resistance. VncR contains two different functional domains, the N-terminal receiver domain and C-terminal effector domain. Here, we investigated VncR C-terminal DNA binding domain (VncRc) structure using a crystallization approach. Crystallization was performed using the micro-batch method. The crystals diffracted to a 1.964 Å resolution and belonged to space group P212121. The crystal unit-cell parameters were a = 25.71 Å, b = 52.97 Å, and c = 60.61 Å. The structure of VncRc had a helix-turn-helix motif highly similar to the response regulator PhoB of Escherichia coli. In isothermal titration calorimetry and size exclusion chromatography results, VncR formed a complex with VncS, a sensor histidine kinase of pneumococcal TCS. Determination of VncR structure will provide insight into the mechanism by how VncR binds to target genes.