Hasil Pencarian  ::  Simpan CSV :: Kembali

"Radiasi merupakan salah satu faktor pembentuk radikal bebas, itu sebabnya petugas yang bekerja di bagian radiasi rentan untuk terpapar radiasi sehingga menimbulkan radikal bebas. Eksperimen ini bertujuan untuk mengetahui seberepa besar pengaruh radiasi terhadap pembentukan radikal bebas pada sampel kuku dan mempelajari proses peluruhan radikal bebas tersebut. Untuk memudahkan eksperimen ini, sampel kuku diradiasi dengan dosis kecil 0,5 Gy, 1 Gy, 3 Gy, 5 Gy dan 10 Gy. Selain itu, untuk mempelajari peluruhan radikal bebas sampel kuku diradiasi dengan dosis besar yaitu 100, 200, dan 300 Gy, kemudian mengukur ulang dengan ESRsetelah satu jam. Yang terakhir adalah pengukuran kuku pada petugas radiasi di sumber gamma cell. Hasil Electron Spin Resonance (ESR) menunjukan bahwa sampel kuku mengandung jumlah radikal bebas yang sesuai dengan banyaknya dosis yang diberikan dan mengalami penurunan jumlah radikal bebas setelah satu jam.

---

Radiation is one factor that forming free radicals, thats why radiation employee has a risk to get irradiated by radiation source nearby . This experiment meant to know how much radiation effect to free radical forming and learn process of freeradical decay. To ease this experiment, fingernail samples were irradiated bygamma with variated dose 0,5, 1, 3, 5 and 10 Gy. Beside that, to learn free radicaldecay, fingernails were irradiated with variated dose 100, 200, and 300 Gy, thenfingernails measured by ESR after one hour. The last is ESR measurement forfingernails of radiation employee. Electron Spin Resonance (ESR) result showedthat fingernails contain number of free radicals as much as radiation dose andbeing decreased after one hour irradiated."

"ABSTRAKA compact, simple and low-cost transversely excited atmospheric (TEA) pressure ultraviolet nitrogen laser {337 nm) has been designed and constructed employing the conventional Blumlein circuit. The measured energy of the output pulse of 337 nm is around 80 -J at 25 kV of charging voltage and l atm operating gas pressure. The beam divergence is found to be 7.7 mrad horizontally and 1.5 mrad vertically. The energy output decreases slightly with increasing gas pressure and gas flow rate, while the beam divergence is relatively stable with respect to the same operating parameters."

"ABSTRACTObservation of fluorescence decay signal of condensed-state molecular samples in the time domain has proved very useful for its identification and analysis. In order to overcome the noise problem in the generally weak fluorescence signals a double-gated boxcar integrator has been designed and incorporated into a spectrometer. The design concept and the working principle of this spectrometer is presented along with detailed description of its subsystems. Performance of this spectrometer has been tested with well-known sample (rhodamine 6G) and the results are duely analyzed. Application of this spectrometer to the measurement of fluorescence spectrum and mean life time of an E. Cali bacteria sample is also described in this work."

"ABSTRACTThe principles of frequency stabilization is to keep constant the optical path length in laser cavity by controlling the laser- tube length. In this system used temperature servo control to control the laser tube length.As reference to an error derived by a sensitive frequency discriminator. Basically the operation of this sensitive frequency discrimantor utilized the longitudinal Zeeman Laser, which splits atomic gain profile.When a longitudinal magnetic field is applied to an internal mirror of single mode He-Ne Laser, the active medium acquires a negative circular dichroism. There fore the intensity of the left cicular polarization (LCP) output of the, laser will be different from the intensity of the right circular polarization (RCP) output and only when the two are simmetrically disposed about the center line will their intensities be equal. This intensity difference as feedback can be detected by passing the output beam throught Wallaston prism and the two orthogonally polarized beams are received by two identical photodiodes. The difference between the output of photodiode as amplified and the resulting signal is passed throught a system controller (PID) before it is fed back as heating or cooling current of peltier elements. This current controls the resonator length thermally and lock the laser frequencies of the two polarized beam symmetrically on either side of the profile."

"ABSTRAKAn N2 laser system that consists of transversely excited atmospheric (TEA) oscillator and transversely excited (TE) amplifier has been designed and constructed. The laser system employs single common spark gap for both oscillator and amplifier. The optimum operating voltage is 15 kV at 2 Hz repetition rate. The measured energy of the output oscillator-amplifier system has maximum value of 55 pJ and beam divergence of 2 mrad horizontally and 1 mrad vertically. Synchronization between the oscillator and amplifier was achieved by varying the gas pressure in amplifier tube, inductance between oscillator and spark gap as well as the optical path between the oscillator and amplifier. The result of its characterization showed that this system is capable to producing BOO % amplification in a single pass. "

"ABSTRACTThe molecular weight of Polymer material can be determined using optical system by measuring the intensity of scattered light at low angle light scattering and its the incident beam, based on Rayleigh scattering have developed by Debye has known as Static Light Scattering. To carry out this measurement, an optical system was constructed using a HeNe laser light with a certain intensity, and the light passed through a polymer solution and its scattered light were then detected using a photo multiplier. To obtain the experimental results, the set-up was tested using a polymer standard, which has been already known its average molecular weight. In this experiment were used the polymer standard with average molecular weight 35000, 110000 and 200000. Furthermore, this optical experiment set-up constant, were used for determining the average molecular weight of the polymer samples. In this experiment a linear curve relation between the optical Rayleigh polymer and the polymer concentrations was constructed, and by extrapolating this linear curve up to zero concentration the molecular weight of polymer can be determined. From the laboratory test we got that the experimental set up could be used for the measurement of polymer, which has the molecular weight larger than 35000 to 200000, with tolerance 4 percent."