Results 21 - 30 of 129692
Results 21 - 30 of 129692. Search took: 0.056 seconds
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[en] A method of mass thickness measurement for dual samples was introduced. The method used equivalent mass attenuation coefficients of single sample to substitute for that of dual samples during the computing process. The errors were computed by simulated experiments. It was found that the method could reach a good accuracy with the computed dual samples and it was a feasible way. The effects of different high voltages combinations were also discussed. It was found that when one high voltage was preset there was an optimization low voltage which would lead to a least relative error for the mass thickness computed. (author)
[en] There is a problem of cross counting of alpha and beta when samples are measured sometime. In order to resolve the problem, the article researches into the range of alpha and beta particles in PIPS detectors. The difference in range results in difference in charge collecting time, so the pulse shape is also different. The characters of pulse shape of alpha and beta particles in PIPS detectors are studied. The rise time of voltage signal is surveyed and the change of rise time in different bias is analysed. Results of the research provided some useful reference to pulse shape discrimination of alpha and beta particles in PIPS detectors. (authors)
[en] The energy dispersive X-ray fluorescence spectrometry (EDXRF) has been used in some departments and fields, and it has become an important tool for the physics and chemistry laboratory. The main performance index of the present EDXRF spectrometry has been introduced, and its development status of the hardware and the software has been summarized. Some new model EDXRF products has been described, the trend and the prospect of the EDXRF has been expected. (authors)
[en] In order to boost accelerator controlling accuracy and improve beam quality, a best filtering method that is Kalman filter was proposed. In the article given general model of the accelerator power and used Matlab to modeling the Kalman filter on the accelerator power model and simulate. Compared the chart of filtering effect, showed that Kalman filter can effectively filter out the effect of random noise. After kalman filtering, Mean square error of the control system was reduced to 23% of the original, Kalman filter especially can reduce the impact of the peak pulse to make the control accuracy improve. (authors)
[en] The count of radon concentration can cause error in the process of transmission because of interfering in the process of measurement by external factors such as electromagnetic waves etc. It makes measurements vary greater than the Expectations. A group of determination value with an average of more than two times of the standard is called outlier value. And which is defined as high level outlier with an average of more than three times of them. In order to meet the Radon Concentration for inspection, the paper makes some necessary improvement on the criterion to adapt itself and estimates the sampled data with Partition method and judgment of Line intersection. The experimental results show that the method is very convenient to reject the mistaken error more effective. The method in this paper can also be used in other fields. (authors)
[en] Single photon counting imaging system is introduced, and principle of workbench is described. The presence of MCP (Micro-channel Plate) pore bias induces image replacement in single photon counting imaging system. This is a precision study. In order to prevent ion feedback and acquire higher electron multiplication, MCP has their pore bias. However, the channel bias can shift the placement of image. To obtain better clear image, we take some steps to correct original image which is shifted. In the paper, through correcting the offset of centroid in charge cloud form MCP to improve the quality of image. (author)
[en] It introduces basic principle of measuring thickness of flake graphite using transmission method of high energy beta rays. An on-line measuring device is designed. Measuring range is 0.2 mm∼3 mm Root- means-square error is better than ±0.5%. (authors)
[en] With the start of the Large Hadron Collider (LHC) at CERN it is now possible to study physics at the TeV-scale for the first time. At this unprecedented energy range it is expected that the Standard Model of particle physics will reach its limits and new phenomena can appear. One of the main goals of the ATLAS experiment is the search for physics beyond the Standard Model. This includes observing supersymmetric particles, which are predicted to have masses of several hundred GeV up to a few TeV. The subject of this thesis is the search for supersymmetric particles in final states with jets and missing transverse energy and the evaluation of the ATLAS discovery potential for supersymmetric particles in the Minimal Supersymmetric Standard Model (MSSM) parameter space for these channels. Different centre-of-mass energies of √(s)=14 TeV, 10 TeV and 7 TeV are assumed. For many R-parity conserving SUSY models, the decay of supersymmetric particles leads to detector signatures characterized by missing transverse energy and multi-jets, sometimes accompanied by leptons. In this thesis, SUSY searches with ≥2-6 jets and 0-2 leptons (electrons, muons) are studied, with a focus on 0-lepton channels, that are expected to be sensitive in large areas of the SUSY parameter space. The search strategies for supersymmetric particles are applied on a sets of differently constrained SUSY models and on several hundred SUSY signals, generated within the pMSSM subspace of the MSSM. The goal of this work is to explore the reach of the performed SUSY searches for completely different decay signatures. It will be shown that the ATLAS SUSY searches cover a large parameter space of SUSY models. The first p-p collisions at a centre-of-mass energy of √(s)=7 TeV in March 2010 allow a comparison of the measured data with the Monte Carlo predictions, in order to see how well the detector response is understood in the context of SUSY specific variables used in the 0-lepton analyzes. All measurements are found to be in agreement with the Standard Model expectations within the associated systematic uncertainties. The results indicate that the ATLAS SUSY searches cover a large parameter space and it is possible to discover or exclude some SUSY models already with a few pb-1 of integrated luminosity.
[en] The study on the natural gas and condensate occurrence in salt, specifically in the salt stock Gorleben-Rambow covers the topics development of salt deposits, salt stocks, crude oil and natural gas, gas and condensate inclusions in evaporite. Experimental data on crude oil borehole studies in Gorleben, natural gas drill holes in the salt stock Rambow, Luechow Z1 - saltstock Wustrow, gas indications, gas occurrences and gas detection are summarized.
[en] Nanotechnology and its applications have captured a worldwide market. Nanomaterials that have been developed using this technology can be incorporated into the devices so that renewable energy can be converted or generated more efficiently. Nanomaterials have the potential to change the way we generate, deliver and use energy. Hydrogen cells are used in auto industry as a viable power source. Compressed hydrogen tanks are used to supply Hydrogen, and Oxygen is used from the air directly. There is no pollution caused by hydrogen fuel cell autos since the only emission is water. Organic dyes (dye sensitizers), which are sensitive to light, can absorb a broader range of the sun's spectrum. A dye-sensitized solar cell has three primary parts. On top is a transparent anode made of fluoride-doped tin dioxide (SnO/sub 2/: F) deposited on the back typically of a glass plate. On the back of this conductive plate is a thin layer of titanium dioxide (TiO/sub 2/), which forms into a highly nanoporous structure with an extremely large surface-area. After soaking the film in the dye solution, a thin layer of the dye is left covalently bonded to the surface of the TiO/sub 2/ . Computational material science and nanoscience can play many critical roles in renewable energy research. These include: finding the right materials for hydrogen storage; finding the most reliable and efficient catalyst for water dissociation in hydrogen production; finding a cheap, environmentally benign, and stable material for efficient solar cell applications; and understanding the photo-electron process in a nanosystem, and hence helping design efficient nanostructure solar cells. (author)