Event reconstruction with MarlinReco at the International Linear Collider

After an overview of the modular analysis and reconstruction framework Marlin an introduction on the functionality of the Marlin-based reconstruction package MarlinReco is given. This package includes a full set of modules for event reconstruction based on the particle flow approach. The status of the software is reviewed and recent results using this software package for event reconstruction are presented.      

26 Al beam production by a solid state laser ion source at TRIUMF

Many experiments carried out at radioactive beam facilities require the production of intense, isotopically clean and isobar free beams of a particular isotope. At TRIUMF the addition of a resonant ionization laser ion source (TRILIS) enables a multitude of new beams and therefore new experiments to be carried out. ²⁶Al was one of the first radioactive ion beams delivered to an experiment using TRILIS. This paper outlines the development of the ²⁶Al ion beam for nuclear astrophysics.      

Ultrafine ash aerosols from coal combustion: Characterization and health effects

Ultrafine coal fly-ash particles, defined here as those with diameters less than 0.5 μm, typically comprise less than 1% of the total fly-ash mass. These particles are formed primarily through ash vaporization, nucleation, and coagulation/condensation mechanisms, which lead to compositions notably different compared to other fine or coarse particle fractions formed by fragmentation. Whereas previous studies have focused on health effects of particulate matter with aerodynamic diameters less than 2.5 μm (PM_2.5) (including both vaporization and fragmentation modes), this paper reports results of interdisciplinary research focused on both characterization and health effects of primary ultrafine coal ash aerosols alone. Ultrafine, fine, and coarse ash particles were segregated and collected from a coal burned in a 20 kW laboratory combustor and two additional coals burned in an externally heated drop tube furnace. Extracted samples from both combustors were characterized by transmission electron microscopy (TEM), wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy, Mossbauer spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Pulmonary inflammation was characterized by albumin concentrations in mouse lung lavage fluid after instillation of collected particles in saline solutions and a single direct inhalation exposure. Results indicate that coal ultrafine ash sometimes, but not always, contains significant amounts of carbon, probably soot originating from coal tar volatiles, depending on coal type and combustion device. Surprisingly, XAFS results revealed the presence of chromium and thiophenic sulfur in the ultrafine ash particles. Although the single direct inhalation study failed to reveal significant health effects, the instillation results suggested potential lung injury, the severity of which could be correlated with the carbon (soot) content of the ultrafines. Further, this increased toxicity is consistent with theories in which the presence of carbon mediates transition metal (i.e., Fe) complexes, as revealed in this work by TEM and XAFS spectroscopy, promoting reactive oxygen species, oxidation–reduction cycling, and oxidative stress.     

New aspects of diphenylbutadiene photochemistry. Regiospecific hula-twist photoisomerization

In EPA glass at liquid nitrogen temperature, the E,E isomer of diphenylbutadiene (DPB) was photostable, while both the Z,E and Z,Z isomers underwent selective HT isomerization at center 1 giving the stable conformer of the double-bond isomerized trans product. That HT-1 was involved rather than the OBF process was shown by results of o,o'-dimethyl-DPB. Formation of unstable trans product corresponded to simultaneous configurational and conformational isomerization. The regioselectivity was found not sensitive to a substituent effect, as shown by the similar reactivity in p,p'- or o,o'-bistrifluoromethyl-DPB.     

Cover Picture

The cover picture shows the X-ray structure of a squalene-hopene cyclase (ribbon diagram) in the center. Squalene and 2,3-oxidosqualene cyclases catalyze the formation of up to five rings and nine stereocenters in transformations that are both complex and elegant. The triterpenes which are arranged around the structure outline the principal reaction pathways for the enzymatic conversion of oxidosqualene (upper semicircle) and squalene (lower semicircle). Further details about these fascinating reactions are discussed by Schulz, Liu et al. on p. 2812 ff.     

电磁理论中算符的一些性质

在本文中,把在不均匀各向异性介质中的麦克斯韦方程看作算符,它定义在一个有界区域,可以被理解为微波技术中的谐振腔。但在这腔中充填着铁氧体,等离子体或其他各向异性介质,这些介质在应用中日益重要。文中证明了在某些μ、ε和边界条件下,算符成为对称。而对称性和自伴性在本征函数展开中带来很多方便;此外我们推导了本征振动的正变性和互易定理。如果不满足对称性,引入伴谐振腔的概念,所谓伴谐振腔在几何形状上和原来的腔相同,但ε、μ和边界条件不一样。它和自伴谐振腔在正交性和互易定理上有某些相似之处。     

Influence of spectral resolution on absorption-line profiles

The convolution of the instrumental function with the initial line profile resulting in the observed intensity distribution has been analyzed by computer studies. Detailed information about its influence on half-width and total absorption is obtained for a wide range of characteristic parameters.     

关于波导管的格林张量函数

本文以本征函数展开的方法,研究了波导管中格林函数的一般性质和形式。为了得到波导管的本征函数(简正波)和格林张量函数的一些关系,我们首先对格林函数作富氏变换,它的象函数在各向同性介质波导中以并矢形式作为最简单的表达方法,而在充有各向异性介质波导中可以表为ABA⁺e^-ikz₀的形式,这里A是坐标矩阵。用这种方法详细推导了均匀各向同性介质波导中的并矢格林函数。 关键词：     

Electron Excited M X-Ray Spectra of the Elements 55≤Z≤58

The M emission spectra of the elements 55 Cs, 56 Ba, 57 La, and 58 Ce were measured using wavelength dispersive X-ray spectrometry with a TAP crystal as the dispersing element. In total, 34M lines were observed, of which only 13 are contained in the compilation of Bearden. M and M of 56 Ba are among the new lines. They have their origin in a similar process to one that is known for 57 La. The interpretation of these spectra is complicated by the strong overlap of some emission lines with the M_IV,V absorption structures, which may lead to anomalous self-absorption effects. Therefore, we have concentrated on spectra taken at a low energy of the exciting electrons, E₀=2.5keV. However, in order to illustrate the anomalous self-absorption effects parts of the 2.5keV spectra, of Ba and La, are shown in comparison with the 10keV spectra.