| 1. |
- Adolph, C., et al.
(författare)
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Interplay among transversity induced asymmetries in hadron leptoproduction
- 2016
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 753, s. 406-411
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Tidskriftsartikel (refereegranskat)abstract
- In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as the Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows quantitative relationships to be established among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.
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| 2. |
- Adolph, David, 1971, et al.
(författare)
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Plasma-assisted molecular beam epitaxy of ZnO on in-situ grown GaN/4H-SiC buffer layers
- 2015
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Ingår i: Frontiers of Materials Science. - : Springer Science and Business Media LLC. - 2095-025X .- 2095-0268. ; 9:2, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- Plasma-assisted molecular beam epitaxy (MBE) was used to grow ZnO (0001) layers on GaN(0001)/4H-SiC buffer layers deposited in the same growth chamber equipped with both N- and O-plasma sources. The GaN buffer layers were grown immediately before initiating the growth of ZnO. Using a substrate temperature of 440 degrees C-445 degrees C and an O-2 flow rate of 2.0-2.5 sccm, we obtained ZnO layers with smooth surfaces having a root-mean-square roughness of 0.3 nm and a peak-to-valley distance of 3 nm shown by AFM. The FWHM for X-ray rocking curves recorded across the ZnO(0002) and ZnO(10 (1) over bar5) reflections were 200 and 950 arcsec, respectively. These values showed that the mosaicity (tilt and twist) of the ZnO film was comparable to corresponding values of the underlying GaN buffer. It was found that a substrate temperature > 450 degrees C and a high Zn-flux always resulted in a rough ZnO surface morphology. Reciprocal space maps showed that the in-plane relaxation of the GaN and ZnO layers was 82.3% and 73.0%, respectively and the relaxation occurred abruptly during the growth. Room-temperature Hall-effect measurements showed that the layers were intrinsically n-type with an electron concentration of 10(19) cm(-3) and a Hall mobility of 50 cm(2).V-1.s(-1).
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| 3. |
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| 4. |
- Adolph, C., et al.
(författare)
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Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons
- 2018
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Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 78:11
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Tidskriftsartikel (refereegranskat)abstract
- Single hadron azimuthal asymmetries of positive and negative hadrons produced in muon semi-inclusive deep inelastic scattering off longitudinally polarised deuterons are determined using the 2006 COMPASS data and also combined all deuteron COMPASS data. For each hadron charge, the dependence of the azimuthal asymmetry on the hadron azimuthal angle f is obtained by means of a fiveparameter fitting function that besides a f-independent term includes four modulations predicted by theory: sin f, sin 2f, sin 3f and cos f. The amplitudes of the five terms have been extracted, first, for the hadrons in the whole available kinematic region. In further fits, performed for hadrons from a restricted kinematic region, the f-dependence is determined as a function of one of three variables (Bjorken-x, fractional energy of virtual photon taken by the outgoing hadron and hadron transverse momentum), while disregarding the others. Except thef-independent term, all themodulation amplitudes are very small, and no clear kinematic dependence could be observed within experimental uncertainties.
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| 5. |
- Aghasi, Keivan, 1983-
(författare)
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Predicting who stays or leaves after the acquisition: : Target’s top manager turnover
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In acquisition of high-tech and knowledge intensive firms, scholars have paid special attention to top managers’ status after the deal. Literature suggests that these managers in particular CEOs if kept in post-acquisition provide coordination capacity for the acquirer to transfer the knowledge and technology from the target to the acquirer while minimizing the disruptive effect of post-acquisition integration process. In addition, the acquirer benefits from human capital embedded in target’s managerial resources; especially in high-tech and knowledge intensive firms where top managers are founders or patent holders. Although the above mentioned argument have been validated by empirical studies showing that top manager’s turnover reduces the post-acquisition performance for the acquirers, multiple empirical studies have reported abnormal managerial turnover shortly after the acquisition. This thesis made an attempt to explain this puzzling phenomenon by investigating on the determinants of the top manager’s turnover of the target in the post-acquisition period. The study finds that in case of CEOs, acquirers do not rely always on coordinating capacity provided by them in post-acquisition. Indeed, the acquirer’s choice of provision of coordination is beyond the target’s CEO retention. The choice of coordination depends on the existing level of coordination capacities and the acquisition’s motivation. In addition, founder-CEOs are more likely to stay after the acquisition because of their valuable firm-specific human capital for the acquirer. However, this value diminishes by the maturity of the target. In addition, similarity in demographic characteristics of the two CEOs (of the acquirer and target) causes social attraction, collaboration and cooperation which ultimately increases the chance that the target’s CEO retention. Finally, diversity within the target’s top management team (TMT) directly increases their chance of departure after the deal. The diversity engenders social frictions, conflicts and coordination inefficiencies.
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| 6. |
- Aghasi, Keivan, et al.
(författare)
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Why diverse top managementteams break up in post-acquisition periods
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper proposes a complementary explanation behind the turnover of target’s top managers in post-acquisition periods. Although human capital and acquisition implementation literature describe managerial retention as desirable, empirical studies have reported significant managerial turnover in acquisition of high-tech and knowledge intensive firms. Borrowing some insights from the team diversity literature, the paper examines the ex-ante diversity among top managers of knowledge-intensive and high-tech firms as an antecedent of their turnover in post-acquisition. We argue that diversity reduces the coordination efficiency necessary to transfer knowledge and facilitate post-acquisition organizational integration, and managers belonging to such teams are more likely to be replaced. Empirical analysis drawing on 2164 top managers in 297 Swedish firms shows that managerial position diversity as a separation, pay disparity and industrial tenure diversity as a variety indeed are associated with managerial exit in three years after the acquisition.
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| 7. |
- Aghasibeig, Maniya, et al.
(författare)
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Laser cladding of a featureless iron-based alloy
- 2012
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 209, s. 32-37
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Tidskriftsartikel (refereegranskat)abstract
- Laser cladding experiments with powder injection technique were carried out to create coatings of Fe-8.1Cr6.4Mn-5.3Si-6.9Mo-3.6C alloy on AISI 1018 steel substrates using a diode laser. Analysis of the clad layers showed that an almost featureless structure was formed at different dilutions between 1% and 4%. The featureless phase with a high hardness of 1155 HV was characterized as a metastable solid solution of e phase. However, the featureless structure appeared to be very brittle with numerous cracks. After heat-treatment, it decomposed into a bainitic structure with a high hardness of 884 HV.
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| 8. |
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| 9. |
- Adolfsson, Vilhelm, et al.
(författare)
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Localized Galerkin Estimates for Boundary Integral Equations on Lipschitz Domanis
- 1992
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Ingår i: SIAM Journal on Mathematical Analysis. - : SIAM. ; 5:23, s. 751-764
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Tidskriftsartikel (refereegranskat)abstract
- The Galerkin method is studied for solving the boundary integral equations associated with the Laplace operator on nonsmooth domains. Convergence is established with a condition on the meshsize, which involves the local curvature on certain approximating domains. Error estimates are also proved, and the results are generalized to systems of equations.
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| 10. |
- Adolph, C., et al.
(författare)
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First measurement of the Sivers asymmetry for gluons using SIDIS data
- 2017
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 772, s. 854-864
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Tidskriftsartikel (refereegranskat)abstract
- The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. For quarks, it was studied in previous measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it was found to be non-zero. In this letter the evaluation of the Sivers asymmetry for gluons is presented. The contribution of the photon-gluon fusion subprocess is enhanced by requiring two high transverse-momentum hadrons. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and the leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/c muon beam scattered off transversely polarised deuterons and protons. With a significance of about two standard deviations, a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero. (C) 2017 The Author(s). Published by Elsevier B.V.
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