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Digitale Medien

Influence of plasma parameters on the growth and properties of magnetron sputtered CNx thin films (2000)

Hellgren, Niklas ; Macák, Karol ; Broitman, Esteban ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 88 (2000), S. 524-532

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ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Carbon nitride CNx thin films were grown by unbalanced dc magnetron sputtering from a graphite target in a pure N2 discharge, and with the substrate temperature Ts kept between 100 and 550 °C. A solenoid coil positioned in the vicinity of the substrate was used to support the magnetic field of the magnetron, so that the plasma could be increased near the substrate. By varying the coil current and gas pressure, the energy distribution and fluxes of N2+ ions and C neutrals could be varied independently of each other over a wide range. An array of Langmuir probes in the substrate position was used to monitor the radial ion flux distribution over the 75-mm-diam substrate, while the flux and energy distribution of neutrals was estimated through Monte Carlo simulations. The structure, surface roughness, and mechanical response of the films are found to be strongly dependent on the substrate temperature, and the fluxes and energies of the deposited particles. By controlling the process parameters, the film structure can thus be selected to be amorphous, graphite-like or fullerene-like. When depositing at 3 mTorr N2 pressure, with Ts〉200 °C, a transition from a disordered graphite-like to a hard and elastic fullerene-like structure occurred when the ion flux was increased above ∼0.5–1.0 mA/cm2. The nitrogen-to-carbon concentration ratio in the films ranged from ∼0.1 to 0.65, depending on substrate temperature and gas pressure. The nitrogen film concentration did, however, not change when varying the nitrogen ion-to-carbon atom flux ratios from ∼1 to 20. © 2000 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.373690

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Digitale Medien

Anisotropies in magnetron sputtered carbon nitride thin films (2001)

Hellgren, Niklas ; Johansson, Mats P. ; Broitman, Esteban ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 78 (2001), S. 2703-2705

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ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Carbon nitride CNx (0≤x≤0.35) thin films, deposited by reactive dc magnetron sputtering in Ar/N2 discharges have been studied with respect to microstructure using electron microscopy, and elastic modulus using nanoindentation and surface acoustic wave analyses. For growth temperature of 100 °C, the films were amorphous, and with an isotropic Young's modulus of ∼170–200 GPa essentially unaffected by the nitrogen fraction. The films grown at elevated temperatures (350–550 °C) show anisotropic mechanical properties due to a textured microstructure with standing basal planes, as observed from measuring the Young's modulus in different directions. The modulus measured in the plane of the film was ∼60–80 GPa, while in the vertical direction the modulus increased considerably from ∼25 to ∼200 GPa as the nitrogen content was increased above ∼15 at. %. © 2001 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1369388

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3

Digitale Medien

Nitrogen bonding structure in carbon nitride thin films studied by soft x-ray spectroscopy (2001)

Hellgren, Niklas

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 79 (2001), S. 4348-4350

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ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Soft x-ray absorption (SXAS) and emission (SXES) spectroscopies were applied to study the nitrogen bonding structure in magnetron sputtered CNx thin films. By comparing with calculated spectra of N in different model systems, N in three main bonding environments can be identified: (i) C(Triple Bond)N bonds, with a sharp SXAS peak at 399.5 eV, (ii) pyridine-like N (i.e., N bonded to two C atoms), with an x-ray absorption resonance at ∼398.5 eV, and (iii) N substituted in graphite, possibly with one sp3 carbon as a neighbor (SXAS energy ∼401 eV). These bondings are present in all CNx films analyzed; however, as shown earlier, the relative intensities between the peaks may vary with the growth conditions. Differences in the coordination of the nearest or second nearest C neighbors only cause slight changes in the peak positions and spectrum shape. © 2001 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1428108

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4

Digitale Medien

Changes in sugar beet mitochondrial DNA induced during callus stage (2000)

Sadoch, Z. ; Majewska-Sawka, A. ; Jazdzewska, E. ; [weitere]

Oxford, UK : Blackwell Publishing Ltd

Plant breeding 119 (2000), S. 0

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ISSN: 1439-0523

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft

Notizen: The organization of mitochondrial DNA was studied in seed-derived plants of sugar beet, Beta vulgaris L., and compared with the structure of DNA isolated from calli propagated in vitro. Tissues representing three genotypes (diploid male sterile, diploid maintainer and diploid fertile) were maintained under in vitro conditions for different periods before the DNA was analysed. Restriction fragment length polymorphism with BamHI and XhoI enzymes, and Southern hybridization with atpA and atp6 homologous probes were used. Hybridization experiments showed conspicuous differences in the organization of both genes in long-term callus cultures (2 years or older). The novel organization of mitochondrial DNA in the calli of the male sterile genotype showed an additional 3.9 kb fragment after hybridization with the atp6, and 7.9 kb and 3.5 kb bands after hybridization with atpA. In the fertile genotype, changes in mitochondrial DNA structure were manifested in the disappearance of a 2.1 kb fragment after probing with atpA. Alterations induced in the mitochondrial genome of the male sterile line showed unique features in mtDNA rearrangements.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1046/j.1439-0523.2000.00460.x

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5

Digitale Medien

COMPUTER MODELS OF EARLY LAND PLANT EVOLUTION (2004)

Niklas, Karl J.

Palo Alto, Calif. : Annual Reviews

Annual Review of Earth and Planetary Sciences 32 (2004), S. 47-66

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ISSN: 0084-6597

Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff

Thema: Geologie und Paläontologie , Physik

Notizen: Computer models are used to mimic the early evolution of ancient vascular plants (tracheophytes). These models have three components: (a) an N-dimensional domain of all mathematically conceivable ancient morphologies (a morphospace); (b) a numerical assessment of the ability (fitness) of each morphology to intercept light, maintain mechanical stability, conserve water, and produce and disperse spores; and (c) an algorithm that searches the morphospace for successively more fit variants (an adaptive walk). Beginning with the most ancient known plant form, evolution is simulated by locating neighboring morphologies that progressively perform one or more tasks more efficiently. The resulting simulated adaptive walks indicate that early tracheophyte evolution involved optimizing the performance of many tasks simultaneously rather than maximizing the performance of one or only a few tasks individually, and that the requirement for optimization accelerated the tempo of morphological evolution in the Silurian and Devonian.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1146/annurev.earth.32.092203.122440

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6

Digitale Medien

Spectroscopic determination of the two-dimensional vibrational potential energy surfaces for the ring-puckering and ring-flapping modes of indan in its S0 and S1(π,π*) electronic states (2002)

Arp, Zane ; Meinander, Niklas ; Choo, Jaebum ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 116 (2002), S. 6648-6655

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ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: The vapor-phase far-infrared, mid-infrared, ultraviolet, Raman, and laser-induced fluorescence spectra of indan have been recorded and analyzed. The far-infrared spectra, which are very similar to those previously reported, together with the Raman and dispersed fluorescence (SVLF) spectra of the jet-cooled molecules were used to reassign the ring-puckering and ring-flapping energy levels for the S0 ground state. These were then utilized to calculate a two-dimensional vibrational potential energy surface (PES) which nicely fits all of the assigned puckering and flapping levels. The PES has a barrier of 488 cm−1 as compared to a previously reported value of 1979 cm−1, which was based on a one-dimensional analysis and earlier assignments. The dihedral angle of puckering is ±30°. Fluorescence excitation spectra of jet-cooled indan together with ultraviolet absorption spectra were used to assign the flapping and puckering levels in the S1(π,π*) electronic excited state. The PES for this state has a barrier of 441 cm−1 and the energy minima correspond to puckering angles of ±39°. The flapping frequency and the stiffness of the PES along the flapping coordinate both decrease substantially in the excited state. The barriers to planarity for both states are higher than those for analogous molecules due to the two –CH2–CH2– torsional interactions. Ab initio calculations do a fairly good job of predicting the experimental barriers for indan and related molecules in their S0 and S1 states. © 2002 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1458926

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7

Digitale Medien

The universal stress protein A of Escherichia coli is required for resistance to DNA damaging agents and is regulated by a RecA/FtsK-dependent regulatory pathway (2000)

Diez, Alfredo ; Gustavsson, Niklas ; Nyström, Thomas

Oxford, UK : Blackwell Science Ltd

Molecular microbiology 36 (2000), S. 0

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ISSN: 1365-2958

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Biologie , Medizin

Notizen: The link between cell division defects and the induction of the universal stress response is demonstrated to operate via the RecA regulator of the SOS response. An insertion in the cell division gene ftsK upregulates uspA in a recA-dependent manner. Unlike true SOS response genes, this upregulation only occurs in growth-arrested cells and is LexA independent. Thus, besides ppGpp-dependent starvation signals, DNA aberrations transduce RecA-dependent signals to the uspA promoter, which only affect the promoter during stasis. Further, we show that ftsK itself, like uspA, is induced in stationary phase and that this induction requires the stringent control modulon rather than activated RecA. Thus, ftsK, like uspA, is regulated by at least two global regulators: ppGpp of the stringent control network and RecA of the SOS modulon. We suggest that UspA is a new bona fide member of the RecA-dependent DNA protection and repair system, as mutants lacking functional UspA were found to be sensitive to UV irradiation and mitomycin C exposure. Moreover, the UV sensitivity of uspA mutants is enhanced in an additive manner by the ftsK1 mutation.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1046/j.1365-2958.2000.01979.x

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8

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God's fund managers: A critical study of stock market investment practices of the Church of England and UK Methodists (2004)

Kreander, Niklas ; McPhail, Ken ; Molyneaux, David

Bradford : Emerald

Accounting, auditing & accountability journal 17 (2004), S. 408-441

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ISSN: 0951-3574

Quelle: Emerald Fulltext Archive Database 1994-2005

Thema: Wirtschaftswissenschaften

Notizen: While the literature contains a number of studies of ethical investment funds, relatively little is known about church investment processes and practices despite the significant role they have played in the development of the sector. This paper attempts to address this lacuna by studying the ethical investment programmes of two UK churches: the Methodist Church and the Church of England. The paper initially explores the relationship between the Judaeo-Christian church and the development of the ethical investment movement. This history reveals an engagement both at the institutional and individual level that challenges the assumed sacred secular divide now commonplace within the literature and the more recent guardian-advocate dichotomy. Second, the paper delineates the way in which the churches theologically conceptualise this engagement and describes how these values are proceduralised through the operation of the funds. The final section provides an immanent critique of church investments both at a performative and theological level. The aim of this concluding section is to engage with the churches in exploring the broader potential for the church in effecting social change.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1108/09513570410545803

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9

Digitale Medien

Business development with electronic commerce: refinement and repositioning (2004)

Aldin, Niklas ; Brehmer, Per-Olof ; Johansson, Anders

Bradford : Emerald

Business process management journal 10 (2004), S. 44-62

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ISSN: 1355-2503

Quelle: Emerald Fulltext Archive Database 1994-2005

Thema: Wirtschaftswissenschaften

Notizen: Electronic commerce enables business development for marketing channel intermediaries and strengthens their existing operations and strategic management. This research shows that electronic commerce provides stepwise business development refinement and repositioning in the form of process change and increased customer service. Based on marketing and logistics literature, a business development model with three developmental phases is proposed in this paper. The findings are based on the electronic commerce development of three intermediaries providing industrial products and services in the northern European market. Refinement is achieved through a focus on activities for internal efficiency, and through changing processes for increased integration, shorter time and lower costs. Repositioning involves extended focus on service improvements, image and customer tailored services. It is found that electronic commerce has not radically reshaped and developed the role of marketing channel intermediaries. Instead, it has strengthened existing business. Future electronic commerce efforts need to be viewed in a business wide development context, including structural change and reaching new segments or markets, to utilise fully the development potential of electronic commerce.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1108/14637150410518329

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10

Digitale Medien

Collaborative supply chain planning using electronic marketplaces (2002)

Rudberg, Martin ; Klingenberg, Niklas ; Kronhamn, Kristoffer

Bradford : Emerald

Integrated manufacturing systems 13 (2002), S. 596-610

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ISSN: 0957-6061

Quelle: Emerald Fulltext Archive Database 1994-2005

Thema: Maschinenbau , Wirtschaftswissenschaften

Notizen: The purpose of this paper is to show how the functionality of electronic marketplaces can facilitate collaborative supply chain planning. Supply chain planning processes are identified and analysed using a supply chain management focus. The paper also gives a brief introduction to a framework for supply chain management and to the typical structure of electronic marketplaces. Furthermore, three collaborative supply chain planning scenarios are defined, and it is shown how collaborative supply chain planning typically could be implemented on an electronic marketplace by the means of a Web-based demonstration. As such, the paper shows how electronic marketplaces can be used to enable supply chain integration.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1108/09576060210448170

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