64 research outputs found
Ett Imperium På Nedgång?: En studie av USA: s Imperium
This is a thesis about the American empire. I also focus my work to see if this American empire is declining. The two main questions I ask and want to answer in this thesis are: is America an empire and is it in decline? I first conclude that America has been an empire ever since the end of the Second World War. The sheer military and economic power of the American empire matches and exceeds the ones before them. The way the US dictate power both in America and across its borders shows that they are not bothered about agreements and treaties that do not suit them. They try to promote and force states to join the capitalistic train and I therefore call them the empire of the free market. Concerning if it is in decline I use two sets of interlinked theories to my study. Paul Kennedys theory of imperial overstretch and a theory of empire resistance. The mix of too much obligations and interests combined with heavy resistance has made empires crumble before. The conclusion is even tough the empire has a lot to deal with it has an ability to change to circumstances and overcome
Reactive magnetron sputtering of tungsten target in krypton/trimethylboron atmosphere
W-B-C films were deposited on Si(100) substrates held at elevated temperature
by reactive sputtering from a W target in Kr/trimethylboron (TMB) plasmas.
Quantitative analysis by X-ray photoelectron spectroscopy (XPS) shows that the
films are W-rich between ~ 73 and ~ 93 at.% W. The highest metal content is
detected in the film deposited with 1 sccm TMB. The C and B concentrations
increase with increasing TMB flow to a maximum of ~18 and ~7 at.%,
respectively, while the O content remains nearly constant at 2-3 at.%. Chemical
bonding structure analysis performed after samples sputter-cleaning reveals C-W
and B-W bonding and no detectable W-O bonds. During film growth with 5 sccm TMB
and 500 oC or with 10 sccm TMB and 300-600 oC thin film X-ray diffraction shows
the formation of cubic 100-oriented WC1-x with a possible solid solution of B.
Lower flows and lower growth temperatures favor growth of W and W2C,
respectively. Depositions at 700 and 800 oC result in the formation of WSi2 due
to a reaction with the substrate. At 900 oC, XPS analysis shows ~96 at.% Si in
the film due to Si interdiffusion. Scanning electron microscopy images reveal a
fine-grained microstructure for the deposited WC1-x films. Nanoindentation
gives hardness values in the range from ~23 to ~31 GPa and reduced elastic
moduli between ~220 and 280 GPa in the films deposited at temperatures lower
than 600 oC. At higher growth temperatures the hardness decreases by a factor
of 3 to 4 following the formation of WSi2 at 700-800 oC and Si-rich surface at
900 oC.Comment: 14 pages, 8 figure
Influence of ionization degree on film properties when using high power impulse magnetron sputtering
Panel Three: The Roles of Juries and the Press in the Modern Judicial System
Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H-2 plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at.% and O contents typically below 0.2 at.% as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of similar to 0.7 eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase delta-ZrH2 (CaF2 type structure) at H content greater thansimilar to 55 at.% and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.5-7 GPa for the delta-ZrH2 films that is slightly harder than the similar to 5 GPa determined for Zr films and with coefficients of friction in the range of 0.12-0.18 to compare with the range of 0.4-0.6 obtained for Zr films. Wear resistance testing show that phase-pure delta-ZrH2 films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of similar to 100-120 mu Omega cm for the delta-ZrH2 films, which is slightly higher compared to Zr films with values in the range 70-80 mu Omega cm
Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets
We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/ T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis
A Genetic Basis of Susceptibility to Acute Pyelonephritis
For unknown reasons, urinary tract infections (UTIs) are clustered in certain individuals. Here we propose a novel, genetically determined cause of susceptibility to acute pyelonephritis, which is the most severe form of UTI. The IL-8 receptor, CXCR1, was identified as a candidate gene when mIL-8Rh mutant mice developed acute pyelonephritis (APN) with severe tissue damage.We have obtained CXCR1 sequences from two, highly selected APN prone patient groups, and detected three unique mutations and two known polymorphisms with a genotype frequency of 23% and 25% compared to 7% in controls (p<0.001 and p<0.0001, respectively). When reflux was excluded, 54% of the patients had CXCR1 sequence variants. The UTI prone children expressed less CXCR1 protein than the pediatric controls (p<0.0001) and two sequence variants were shown to impair transcription.The results identify a genetic innate immune deficiency, with a strong link to APN and renal scarring
High power impulse magnetron sputtering under industrial conditions
In this thesis, the recent development step of magnetron sputtering, termed high power impulse magnetron sputtering (HiPIMS) has been studied. Compared to conventional magnetron sputtering HiPIMS provides a higher plasma density which can ionise the sputtered material. The beneficial influence of the coating properties due to this ionisation has been extensively shown in academic publications. Here, industrial conditions, i.e. no substrate heating and high vacuum conditions have been used during the studies, of which one was performed in an industrial deposition system. For eight metallic targets, films were deposited with HiPIMS and conventional sputtering. The films were evaluated by Rutherford back scattering analysis, scanning electron microscopy, and profilometry. It was found that the density of the HiPIMS grown films exhibited a statistically significant higher density of approximately 5-15% in comparison to films deposited using DCMS under identical conditions. A global plasma model was employed to evaluate the degree of ionisation for some of the target materials, and process conditions used in the study. Conformity between density increase and degree of ionisation as assessed by the plasma model was confirmed. The influence of using HiPIMS during reactive sputtering of TiC was also studied. A metallic Ti target was sputtered in a gas mixture of Ar and C2H2. The coatings were evaluated by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, 4 point probe resistivity measurements, and nanoindentation. The coatings were found to be nanocomposite TiC/a-C:H. For the HiPIMS process the transition zone between metallic and compound target states was found to be significantly expanded over a wide reactive gas flow range. The implications of choice of deposition method for coating composition, chemical structure, as well as electrical and mechanical properties were evaluated for DCMS and HiPIMS. The process behaviour was suggested to be due to the pulsed nature of the HiPIMS, the high plasma density, and ion content of the particles reaching the substrate
Fundamental aspects of HiPIMS under industrial conditions
Fundamental aspects of the high power impulse magnetron sputtering (HiPIMS) process and its implication for film growth under industrial conditions have been studied. The emerging HiPIMS technique exhibits a higher plasma density and an enhanced degree of ionisation of sputtered material as compared to conventional direct current magnetron sputtering (DCMS). The increased ionisation permits control of the deposition flux and facilitates an intense ion bombardment of the growing films. The latter allows for growth of well adherent, smooth, and dense thin films. Moreover, the technique offers increased stability of reactive processes, control of film phase constitution as well as tailoring of e.g. optical and mechanical properties. In the present work, it was shown, for eight different metals (Al, Ti, Cr, Cu, Zr, Ag, Ta, and Pt), that films grown using HiPIMS exhibit a 5-15% higher density than films grown using DCMS under otherwise identical conditions. Through simulations of the fundamental ionisation processes in the plasma discharge, a correlation between high ionisation degree and film densification was established. The densification was suggested to be a consequence of increased ion irradiation of the growing films in the HiPIMS case. This knowledge was used to investigate the degree of ionisation in the deposition flux required for film modifications. Using a hybrid process, where DCMS and HiPIMS were combined on a single Cr cathode, independent control of the degree of ionisation from other experimental parameters was achieved. The results showed that the majority of the ion irradiation induced modifications of surface related film properties occurred when ~40% of the total average power was supplied by the HiPIMS generator. Under such conditions, the power normalised deposition rate was found to be ~80% of that of DCMS. This was attributed to a reduction in back-attracted ionised sputtered material, which is considered to be the main reason for the low deposition rate of HiPIMS. Thus, enhanced film properties were attainable largely without sacrificing deposition rate. Compound carbide and boride films were synthesised using both reactive processes and compound sources. Reactive deposition of TiC/a-C:H thin films using C2H2 as reactive gas, i.e. carbon source, was demonstrated. It was found that the high plasma density processes (i.e. HiPIMS) facilitated growth conditions for the film structure formation closer to thermodynamic equilibrium than did processes exhibiting lower plasma densities (i.e. DCMS). This was manifested in a high stoichiometry of the carbide phase, whilst excess a-C was removed by physical sputtering. Moreover, the feasibility of using HiPIMS for thin film growth from a compound source, obtaining the same composition in the films as the sputtering source, was demonstrated through synthesis of ZrB2 films
Fundamental aspects of HiPIMS under industrial conditions
Fundamental aspects of the high power impulse magnetron sputtering (HiPIMS) process and its implication for film growth under industrial conditions have been studied. The emerging HiPIMS technique exhibits a higher plasma density and an enhanced degree of ionisation of sputtered material as compared to conventional direct current magnetron sputtering (DCMS). The increased ionisation permits control of the deposition flux and facilitates an intense ion bombardment of the growing films. The latter allows for growth of well adherent, smooth, and dense thin films. Moreover, the technique offers increased stability of reactive processes, control of film phase constitution as well as tailoring of e.g. optical and mechanical properties. In the present work, it was shown, for eight different metals (Al, Ti, Cr, Cu, Zr, Ag, Ta, and Pt), that films grown using HiPIMS exhibit a 5-15% higher density than films grown using DCMS under otherwise identical conditions. Through simulations of the fundamental ionisation processes in the plasma discharge, a correlation between high ionisation degree and film densification was established. The densification was suggested to be a consequence of increased ion irradiation of the growing films in the HiPIMS case. This knowledge was used to investigate the degree of ionisation in the deposition flux required for film modifications. Using a hybrid process, where DCMS and HiPIMS were combined on a single Cr cathode, independent control of the degree of ionisation from other experimental parameters was achieved. The results showed that the majority of the ion irradiation induced modifications of surface related film properties occurred when ~40% of the total average power was supplied by the HiPIMS generator. Under such conditions, the power normalised deposition rate was found to be ~80% of that of DCMS. This was attributed to a reduction in back-attracted ionised sputtered material, which is considered to be the main reason for the low deposition rate of HiPIMS. Thus, enhanced film properties were attainable largely without sacrificing deposition rate. Compound carbide and boride films were synthesised using both reactive processes and compound sources. Reactive deposition of TiC/a-C:H thin films using C2H2 as reactive gas, i.e. carbon source, was demonstrated. It was found that the high plasma density processes (i.e. HiPIMS) facilitated growth conditions for the film structure formation closer to thermodynamic equilibrium than did processes exhibiting lower plasma densities (i.e. DCMS). This was manifested in a high stoichiometry of the carbide phase, whilst excess a-C was removed by physical sputtering. Moreover, the feasibility of using HiPIMS for thin film growth from a compound source, obtaining the same composition in the films as the sputtering source, was demonstrated through synthesis of ZrB2 films
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