2,197 research outputs found
Macroporous silicon membranes as electron and x-ray transmissive windows
Macroporous silicon membranes are fabricated whose pores are terminated with 60 nm thin silicon dioxide shells. The transmission of electrons with energies of 5 kV-25 kV through these membranes was investigated reaching a maximum of 22% for 25 kV. Furthermore, the transmission of electromagnetic radiation ranging from the far-infrared to the x-ray region was determined. The results suggest the application of the membrane as window material for electron optics and energy dispersive x-ray detectors
Muon capture on nuclei with N > Z, random phase approximation, and in-medium renormalization of the axial-vector coupling constant
We use the random phase approximation to describe the muon capture rate on
Ca,Ca, Fe, Zr, and Pb. With
Ca as a test case, we show that the Continuum Random Phase
Approximation (CRPA) and the standard RPA give essentially equivalent
descriptions of the muon capture process. Using the standard RPA with the free
nucleon weak form factors we reproduce the experimental total capture rates on
these nuclei quite well. Confirming our previous CRPA result for the
nuclei, we find that the calculated rates would be significantly lower than the
data if the in-medium quenching of the axial-vector coupling constant were
employed.Comment: submitted to Phys. Rev.
ITIL and the Creation of Benefits: An Empirical Study on Benefits, Challenges and Processes
Over 90 percent of companies are estimated to use IT Service Management (ITSM) frameworks, yet there is little research on their benefits to the Information Technology (IT) department and the business units. An international survey of 503 firms was conducted to examine the benefits of the IT Infrastructure Library (ITIL), the de-facto ITSM framework, specifically on how these benefits evolve as companies increase their adoption of the ITIL model. Also studied are the perception of challenges of the implementation and the number of ITIL processes implemented in relation to the progress of the adoption of ITIL. Results indicate that as the maturity of implementation increases, the perception of challenges decreases. Findings also show that as the maturity of implementation increases, the number of realized benefits increases, as well as the number of implemented ITIL processes. Implications for practitioners and researchers are also discussed.12 page(s
Impact of IT Service Management Frameworks on the IT Organization An Empirical Study on Benefits, Challenges, and Processes
Over 90 percent of companies are estimatedto use IT Service Management(ITSM) frameworks, yet there is little researchon their benefits to the InformationTechnology (IT) department andthe business units. An international surveyof 491 firms was conducted to assessthe benefits of the IT InfrastructureLibrary (ITIL), the de-facto ITSM framework,specifically on how these benefitsevolve as companies increase theiradoption of the ITIL model. Also studiedare the perception of challenges ofthe implementation and the number ofITIL processes implemented in relationto the progress of the adoption of ITIL.Results indicate that as the maturity ofimplementation increases, the perceptionof challenges decreases. Findingsalso showthat as thematurity of implementationincreases, the number of realizedbenefits increases, as well as thenumber of implemented ITIL processes.Implications for practitioners and researchersare also discussed
Neutrino induced transitions between the ground states of the A=12 triad
Neutrino induced reactions on C, an ingredient of liquid
scintillators, have been studied in several experiments. We show that for
currently available neutrino energies, 300 MeV, calculated
exclusive cross sections CN for both muon
and electron neutrinos are essentially model independent, provided the
calculations simultaneously describe the rates of several other reactions
involving the same states or their isobar analogs. The calculations agree well
with the measured cross sections, which can be therefore used to check the
normalization of the incident neutrino spectrum and the efficiency of the
detector.Comment: 9 pages REVTEX, 2 postscript figures, text and figures available at
http://www.krl.caltech.edu/preprints/MAP.htm
Signal for supernova and neutrinos in water \v{C}erenkov detectors
We suggest that photons with energies between 5 and 10 MeV, generated by the
() and () reactions on O, constitute a
signal which allows a unique identification of supernova and
neutrinos in water \v{C}erenkov detectors. We calculate the yield of
such events and estimate that a few hundred of them would be detected
in Superkamiokande for a supernova at 10 kpc distance.Comment: 8 pages, RevTex 3.0, figures and text available at
http://www.krl.caltech.edu/preprints/MAP.htm
Rydberg excitation of a single trapped ion
We demonstrate excitation of a single trapped cold Ca ion to
Rydberg levels by laser radiation in the vacuum-ultraviolet at 122 nm
wavelength. Observed resonances are identified as 3dD to 51 F, 52 F
and 3dD to 64F. We model the lineshape and our results imply a
large state-dependent coupling to the trapping potential. Rydberg ions are of
great interest for future applications in quantum computing and simulation, in
which large dipolar interactions are combined with the superb experimental
control offered by Paul traps.Comment: 4 pages, 3 figure
Ultrasonic Assessment of Permanent Joints of Powder Metallurgy Parts Obtained by Pulsed Electromagnetic Field
Radial pressing by a pulsed electromagnetic field (PEMF) is a fast and effective way of rigid connection of thin-walled powder parts. The quality of joining depends on well-chosen intensity and uniformity of the applied PEMF. The difficulty of non-destructive tests of joints by standard ultrasonic flaw detectors is often caused by a curved shape and a small radius of parts. The coarse-grained structure and porosity of powder parts cause a strong attenuation of ultrasound at frequencies above 3 MHz. Two ultrasonic methods were compared for sensitivity to weak and tight connections of “bush-on-bush” and “bush-on-rod” joints – pulse-echo and time-of-flight (TOF). Bushes were made of powder bronze graphite. The pulse-echo method was implemented using a commercial flaw detector with a 3MHz dual-element probe. A custom setup with quasi-point transducers at 2MHz was used in the TOF method. Weak joining between parts resulted in increased reflection of ultrasound from the bonded zones between the parts and the corresponding changes in the ultrasonic patterns. Both methods are potentially applicable to quality assurance in PEMF joining, where TOF is preferable for testing small curved parts
Towards Managing IT Complexity: An IT Governance Framework to Measure Business-IT Responsibility Sharing and Structural IT Organization
For large enterprises, IT governance is a major lever to influence the way how IT enables business. The authors hypothesizethat a part of IT governance, namely business-IT responsibility sharing and structural IT organization, has a strong influenceon IT architecture complexity of large enterprises. IT complexity is challenging CIOs of large enterprises all over the worldday-by-day. Yet, IT complexity so far has been analyzed by scientific research only to a small degree. To prove or falsify thehypothesis that IT governance influences IT architecture complexity, the authors developed concepts to measure both aspectswith a framework. In this research, the concept for business-IT responsibility sharing and its scientific background arepresented. The IT complexity measurement concept is shown, focusing on IT architecture complexity. An outlook for thisresearch, an empirical study that is currently in progress is given
The role of market orientation and innovation capability in export performance of small-and medium-sized enterprises: a Latin American perspective
Purpose - This study aims to extend the existing base of knowledge of proactive and reactive market orientation and innovation capability by testing their impact on the export performance of emerging-market small- and medium-sized enterprises (SMEs) in a Latin American context. Design/methodology/approach - This paper is a replication study, and its data were collected through a survey answered by general, marketing, sales or export managers at 155 Mexican SMEs. The research model was tested using partial least squares. Findings - The study results indicate that innovation capability and reactive market orientation are drivers of export performance in Latin American SMEs. Moreover, proactive market orientation has been found to have an indirect effect on export results. Practical implications - This study highlights to managers of Latin American SMEs the importance of capability development and deployment to improve export performance. Social implications - SMEs enabled by strategic and technological innovation based on current and latent customer needs can advantageously perform in foreign markets and can drive economic growth and social and human development in Latin America. Originality/value - Recent studies have focused on emerging-market enterprises and the necessity of developing dynamic capabilities to achieve internationalisation. This study extends previous research by assessing the robustness and generalizability of drivers in export performance for manufacturing SMEs in Latin America. In particular, it provides empirical insights on the capabilities to develop by Latin American SMEs to achieve better export performance
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