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Quark Jet Fragmentation

A semiclassical model is presented for the way the energy of a fast quark is transformed into observable hadrons. It reproduces the features of 1 + 1 dimensional QED (the Schwinger model) concerning a flat rapidity distribution in the central region. In particular the model predicts that the probability to find a meson containing a leading quark is independent of the Feynman scaling variable. Also

Drop size distribution and LWC in Po valley fog

In this paper results are presented of ground-based fog microphysical measurements obtained during the CHEMDROP experiment in the Po Valley (Northern Italy) in November 1994. Altogether about 85 hours of drop microphysical data are analyzed. At the beginning of the experiment a comparison of some of the different microphysical instruments, operated during the experiment, was performed. It has reve

Chemical speciation of aerosol samples by ion beam thermography

Ion beam thermography (IBT) is a technique for the determination of chemical compounds. The IBT setup combines the multielemental ion beam techniques PIXE, PESA, pNRA and cPESA with thermography. During thermography the temperature is gradually increased up to the order of 600 °C, causing vaporisation of chemical compounds at specific temperatures. The combination of methods display low detection

The use of PIXE and complementary ion beam analytical techniques for studies of atmospheric aerosols

PIXE is nowadays a routine analytical technique in the study of atmospheric aerosols. If it aspires to continue to be so in the future, it will have to compete with a range of other powerful analytical techniques, and outperform them in some respect. It will be shown how PIXE can indeed play an important role in future studies of atmospheric aerosols. For clarification, two concrete examples will

A high-sensitivity method for hydrogen analysis in thin targets

A sensitive and fast method for hydrogen analysis has been developed. The method is based on a technique where a proton beam of a few MeV impinges on the target and the elastically scattered proton and the recoiling target hydrogen nucleus are detected in coincidence. The method makes use of the difference in time of flight and requires no energy determination. The system consists of two thin, lar

A relative humidity processing method for the sampling of aerosol particles with low growth‐ability

A method for the fractionation of aerosol particles with respect to size and ability to grow with an increased relative humidity has been developed. The system consists of cascade impactors, diffusion driers, a humidifier and a temperature stabiliser. Diffusion driers were designed and the vapour penetration was modelled below 20%. A humidifier which can be operated with an output relative humidit

Commodification of Public Space: The Case of Hong Kong

Much of the debates surrounding public space is currently centred on privatisation and how it has contributed to the erosion of publicness in public space. However, public ownership and management of public space does not necessarily guarantee its accessibility, inclusivity and publicness – highly curated and regulated public space that are publicly funded and operated can be just as restrictive a

A statistical model for quark fragmentation into mesons with emphasis on vector meson contributions

This paper is the first part of a program to deal with the relative importance of the different effects in a colour dipole field when the field energy is transformed into hadrons according to a statistical scheme with the sole constraints coming from energy and momentum conservation and the requirements of scaling. In this paper we treat the meson distributions from quark fragmentation with partic

Skin autofluorescence as a measure of advanced glycation end product levels is associated with carotid atherosclerotic plaque burden in an elderly population

BACKGROUND: Advanced glycation end product is an established risk marker in diabetic vascular disease, but its possible associations with atherosclerosis in a general population are yet to be investigated. We studied the degree of carotid atherosclerosis and its association with skin autofluorescence in an elderly population.METHODS: Carotid ultrasound and skin autofluorescence measurements were p

Experimental cross sections for Bremsstrahlung production by the impact of MeV protons on low-Z targets

The production of continuously distributed X-rays by the impact of protons of 1.9-3.0 MeV for X-ray energies between 4 and 6.5 keV, and 1.9-2.65 MeV for X-ray energies between 1.7 and 4 keV has been investigated. Five different target types have been irradiated: polyethylene, polystyrene, carbon. KaptonTM and MylarTM. The results are presented as absolute cross sections for continuous X-ray produc

On the charge limit for crystallizing particles

The electrical charge limit of crystallizing sodium chloride droplets has been studied. Moderately charged sodium chloride solution droplets were dried to highly charged residual particles. The charge limit was found to be near the Rayleigh charge limit for saturated sodium chloride droplets of the same size as the residual particle. The charge loss was not found to affect the particle size to a d

Characterization of the response function of a Si(Li) detector using an absorber technique

The non-Gaussian response function of a Si(Li) detector has been measured for characteristic Kα X-rays in the energy interval 1.5-8.6 keV using an absorber technique. The method is based on the different response to an attenuating absorber placed in front of the detector for the detector tail as compared to fully absorbed photons in the same position in the spectrum. The shape of the tail of a Kα

The relationship between the meson, baryon, photon and quark fragmentation distributions

The ideas presented in an earlier note on the relationship between the quark fragmentation distributions as measured in leptoproduction and the one particle distributions in the mesonic fragmentation regions of hadronic interactions are carried further to photoproduction and to the baryon fragmentation distributions. The results are as before interpreted in terms of a simple additive quark model w

PIXE and proton microprobe advances at the Lund Institute of Technology

A review of recent advances in high-energy ion beam analysis at the Lund Institute of Technology is presented. A nonvacuum specimen chamber allows chemical speciation using a combination of ion beam analysis and controlled heating. The development of a new versatile scanning proton microbeam based on a new dedicated accelerator, an achromatic triplet lens and an advanced specimen chamber is outlin

Ion beam thermography - analysis of chemical compounds using ion beam techniques

The analytical technique of ion beam thermography (IBT) is reported for the first time. IBT is a technique for the determination of chemical compounds. This IBT setup combines the multielemental ion beam technique's particle-induced X-ray emission (PIXE) and particle elastic scattering analysis (PESA) with thermography. A large number of elements are monitored with PIXE (Z > 14) and PESA (hydrogen

Implications of a large vector meson production on quark jet fragmentation and large p T reactions

A large vector meson production in quark jet fragmentation implies characteristic differences between the kaon and pion spectra. This prediction is verified in a recent SLAC-MIT experiment. Similar considerations are relevant for the c-quark fragmentation into D-mesons, as observed in ν scattering experiments.The difference in kaon and pion spectra provides a test of the hard quark-quark scatterin

Inner-shell ionization processes in low Z (Z ≤ 20) elements by proton bombardment

K-shell X-ray ionization cross section from thin targets of P, S, Cl, K and Ca by proton impact in the energy range of 1.0-5.0 MeV are reported using a Si(Li) detector. Our experimental results are compared with previous very scanty available data and with ECPSSR theory. Data for P are reported for the first time. Results for S, Cl and K in this wide energy range are also new data. Our results sho