Wyniki wyszukiwania - BazTech

1

A study on the designs of the resonator for reducing resonance noise of intake system in vehicle

Xu Ch., Samoilenko D., Cho H.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2018

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z. 1/115

5--11

EN

In the present paper, a pipe integrated resonator that can reduce the space occupation in the engine room will be introduced. A direct comparison with the Helmholtz resonator through the change of the neck will be considered as well, and possible achievement in performance improvement will be presented. In addition to the basic design of the resonator, another(an alternative) design is offered. An alternative solution suits the engine miniaturization concept taking in to account the possibility of supercharger installation. In such a case the engine compartment becomes very narrow and difficulties with the mounting of existing resonators occurs. The finite element analysis is used for the simulations of the flow processes in resonators and perforated tubes. The effects of reduction in discharge noise are reached.

PL

W niniejszym artykule zaprezentowano nową konstrukcję zintegrowanego rezonatora o zmniejszonych wymiarach, która zajmuje mniej przestrzeni w komorze silnika samochodu. Dokonano bezpośredniego porównania nowej konstrukcji o udoskonalonej geometrii z rezonatorem Helmholtza, przewidując polepszenie sprawności urządzenia. Dodatkowo do podstawowej konstrukcji rezonatora zostało zaproponowane rozwiązanie alternatywne. Alternatywne rozwiązanie spełnia wymóg minimalnych wymiarów zintegrowanego rezonatora, umożliwiając jednocześnie instalację sprężarki mechanicznego układu doładowania silnika. W omówionym przypadku przestrzeń komory silnika była by zbyt mała do zamontowania standardowego rezonatora. Wykorzystano metodę elementów skończonych do przyprowadzenia badania symulacyjnego zjawisk przepływowych w rezonatorze oraz rurach perforowanych. Uzyskano efekt zmniejszenia hałasu wskutek odprężenia powietrza w układzie dolotowym.

2

Effect Of Carbon Nanotubes On The Properties Of Spark Plasma Sintered ZrO2/CNT Composites

Shim D. H., Jung S. S., Kim H. S., Cho H., Kim J. K., Kim T. G., Yoon S. J.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1315--1318

EN

Zirconia matrix ZrO2/CNT composite materials reinforced with multiwall carbon nanotubes were fabricated using a spark plasma sintering technique. The effects of the amount of CNTs addition, sintering temperature and sintering pressure on the properties of the resulting ZrO2/CNT composites were examined. 0 to 9 vol. % CNTs were dispersed in zirconia powder, and the resulting mixture was sintered. The electrical conductivity, hardness, flexural strength, and density were measured to characterize the composites. The friction and wear properties of the composites were also tested. The flexural strength and friction coefficient of the composites were improved with up to 6 vol.% of CNT addition and the flexural strength showed a close relationship with the relative density of the composite. The electrical conductivity increased with increasing proportion of the CNTs, but the efficiency was reduced at more than 6 vol.% CNTs.

3

A New 3D Sensor System by Using Virtual Camera Model and Stereo Vision for Mobile Robots

Lee H., Kim M. N., Cho H.

Journal of Automation Mobile Robotics and Intelligent Systems

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2008

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Vol. 2, No. 4

38-44

EN

So many researches have been conducted to develop 3D sensing method for mobile robots. Among them, the optical triangulation, a well-known method for 3D shape measurement, is also based on active vision sensing principle for mobile robot sensor system, so that the measurement result is robust to illumination noises from environments. Due to this advantage it has been popularly used. However, to obtain the 3D information of environment needs a special scanning process and scanning actuators need. To omit this scanning process multi-line projection methods have been widely researched. However, they suffer from an inherent limitation: The results of multi-line projection method commonly have measurement errors because of 2 -ambiguity caused by regularly repeated multiline laser pattern. In this paper, to overcome 2 -ambiguity effectively, we introduce a novel sensing method for a 3D sensing system using multi-line projection and stereo cameras, based on the virtual camera model and stereovision algorithm. To verify the efficiency and accuracy of the proposed method, a series of experimental tests is performed.

4

Electron impact excitation and dissociation of halogen-containing molecules

Kitajima M., Suzuki R., Tanaka H., Pichl L., Cho H.

Nukleonika

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2003

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Vol. 48, nr 2

89-93

EN

A systematic analysis of the absolute differential cross sections (DCSs) for electron scattering by halogen-containing molecules CF3X (X = H, F, Cl, Br, I) has been performed with impact energy and scattering angle ranging from 1.5 to 100 eV and 15 to 130°, respectively. Three of the results of these experiments are described in the present report. Firstly, a clear difference is demonstrated in the elastic-scattering cross section angular distributions of polar and nonpolar molecules with the substitution of one of the F atoms in CF4 for a H, Cl, Br or I atom. Secondly, vibrational excitation spectra of the unresolved composite modes (mainly CF3 stretching) for CF3X reveal a common broad structure in the region from 7 to 9 eV due to shape resonance. The third result presented is the observation of a low-lying electronic state of CF3Cl, CF3Br, and CF3I. This feature is enhanced at lower incident energies and larger scattering angles. Also discussed are some preliminary results on the formation of negative and neutral fragments from SiF4 and CH4 by electron impact.