Kekonduksian Terma Filem Polimer Lut Sinar, OHP

A measurement of thermal conductivity of OHP (overhead projector) polymer films is reported. Thermal conductivity of PVC, 3M infra-red and triacetate films was measured using a simple, inexpensive home-made apparatus. The values obtained were: (0.567 ± 0.005) Wm-1K-1, (0.312 ± 0.005) Wm-1K-1, and (0.171 ± 0.005) Wm-1K-1. The thermal conductivity of mylar film was also measured and its value of (0.212 ± 0.005) Wm-1K-1 is in good agreement with figures previously reported. It has been shown that the heat resistance of polymer films is linearly dependent on the thickness of the film in accordance with the theory

Peranan Paras-paras 3p0 dan 3p2terhadap Pekali Pengionan Sekunder dalam Nyahcas Townsend

The contribution of the 3Po and 3Po levels to the secondary ionization coefficient in a Townsend discharge are discussed. In the case of a research grade krypton gas sample, the theoretical values of 0 I a (the dominant process in the range Hlp < 50 volt cm- 1 to"-1 ) are in good agreement with the ex, perimental values of w I a. However, in the case of purified research grade krypton gas samples, it seems likely that only atoms in the 3P0 level contributed to the secondary ionization coefficient

Ionization Coefficients and Breakdown Potential in Krypton

Ionization currents in research grade krypton between plane parallel gold-plated electrodes at separation up to 3 cm were measured in the range of 14 < E/P -:(" 200 volt cm - 1 torr -1 and 2 < p.-:(" 130 torr where E is the applied electric field and p ** is the gas pressure. The values of ionization coeffidents of/P deduced from these measurements were lower than the values obtained by Kruith of(1940) but higher than the values obtained by Dutton et al. (1983), in the range of E/P < 200 volt cm -1 torr -1. Within the limit of experimental error, /P was found to be a function of E/P only. The measured values of breakdown potentials were in good agreement with the values calculated from the breakdown criterion and satisfied the similarity principle

Pencirian Plasmon-Polariton Permukaan Melalui Gandingan Parutan

Surface plasmon polariton mode may be excited by photons using grating coupling to provide the necessary extra momentum. Reflectivity measurements at 632.8 nm were carried out on three modulated grating gold films. The gold films were deposited by vacuum evaporation on a silica grating at base pressure for 1O-6 torr. By rotating the grating in azimuth angle direction, where the grooves of the grating are no longer perpendicular to the plane of incidence, the symmetry of the system is broken and polarization conversion phenomenon is introduced. This conversion is strongly enhanced when SPP mode is excited. The dependence of this conversion on angle of incidence and azimuthal angle is discussed in detail. When the grooves are at about 45° to the plane of incidence, maximum conversion is observed

Penguatan-parutan Terhadap Mod-mod Elektromagnet pada Pandu Gelombang Organik Tripalmitin

Grating-enhancement and characterization of electromagnetic modes in organic waveguides are presented. The intensity of P and S polarized light reflected from the gold grating with organic tripalmitin coating at varying twist angles was measured as a function of angle of incidence. The characteristic behaviour of TE and TM modes in terms of twist angles is discussed in detail. It was discovered that the maximum P-S conversion of TEl' TE2 and TM2 modes occurred at twist angles of 40, 50 and 64° respectively. In this experiment it was found that organic tripalmitin is a good candidate for waveguide material and needs to be studied in more detail

Kesan Pelarut Terhadap Pemalar Optik Lamtan Organik Laser Dye

The optical constants n and k of R6G and Fluorscein in methanol and ethanol (at a particular concentration of 5 X 10-5 molar) as a function of wavelength are reported. The extinction coefficient k and the refractive index n were measured in the range of wavelength 200-700 nm and 540-700 nm respectively. The results showed that the refractive index n obtained for R6G and Fluorescein in ethanol was significantly higher than in methanol

Thermally induced nonlinear refraction of gold and silver polyvinvinylpyrrolidone nanofluid

The nonlinear refractive index of metal Au and Ag nano-fluids prepared by γ-radiation method was investigated by a single beam Z-scan technique. Under CW 532 nm laser excitation with power output of 40 mW, the Au and Ag nano-fluids show a large thermal-induced nonlinear refractive index. In the present work it was determined that the nonlinear refractive index for both Ag and Au nano-fluids are -4.80×10-8 cm2/W and -3.85×10-8 cm2/W respectively. The values of Δn0 for both samples were also calculated to be -2.05×10-4 and -1.64×10-4 respectively. Our measurements also confirmed that the nonlinear phenomenon was caused by the self-defocusing process making them good candidates for non linear optical devices

Study of Photobleaching Mechanism in Methylene Blue Sensitized Gelatin Using a Single Beam UV-Vis. Fibre Optics Spectrophotometer

In the present study, we have investigated the photobleaching of the methylene blue (MB) doped in Gelatin matrix using uv-visible fibre optic spectrophotometer. Illumination of the sample by uv-visible radiation resulted in a decrease of the absorption peak with the increasing of irradiation time. This indicates that upon irradiation MB dye molecule is photoreduced to its leuco form (colorless) of MB. The present experimental results indicate a slower photobleaching process occurring at higher concentration of dye doped in gelatin matrix. This study shows that the MB doped in gelatin solid matrix opens a new possibility in realtime holography applications

Pengesan Optik, Piezoelektrik-fotoakustik

An optical detector based on piezoelectric detection of the photo acoustic effect in an absorbing metal plate is reported. Such a detector has been used in an experiment for measuring a Gaussian laser beam diameter using the knife-edge method. The responsivity of the detector varied from 4.05J.LV/mW at 68Hz to 1.25J.LV/mW at 211Hz. The Gaussian laser beam diameter obtained from the experimental data is (0.88 ± 0.02)mm and this value is comparable with the value stated in the laser specification note