Ein Konzept für die Datenhaltung in der fertigungsnahen Mikrosystemtechnik

Diese Arbeit präsentiert Ergebnisse, die im Rahmen des PRINCE-Projektes am Institut für Mikrosystemtechnik generiert wurden. PRINCE steht für PRocess INformation and management CEnter und beschäftigt sich mit der automatisierten Entwurfsunterstützung für die Mikrosystemtechnik. Besonderes Augenmerk wurde hierbei auf die fertigungsnahen Aspekte des Entwurfs gelegt, da diese in bisherigen Lösungen nur ungenügend beachtet werden. Im Rahmen der Arbeit wurde deshalb eine umfassende Analyse der Problematik durchgeführt. Eines der Ergebnisse war die Erkenntnis, dass beim fertigungsnahen Entwurf viele Daten anfallen, die alle in enger Beziehung stehen. Die geeignete Datenhaltung ist deshalb ein zentraler Punkt des Entwurfs. Ausgehend von dieser Erkenntnis wurde untersucht, welche aus der Informatik bekannten Methoden im Bereich Datenbank-Management geeignet sind. Als Ergebnis wird ein relationales Datenbankmodell vorgestellt, mit dem die gesammelten Daten auf sinnvolle Weise gespeichert und miteinander in Beziehung gebracht werden können. Außerdem wird eine Erweiterung dieses Modells um Methoden aus der Objektorientierung präsentiert, die eine hierarchische Darstellung der Daten durch Vererbung und Mehrfachvererbung ermöglicht. Mit dem Software-System PRINCE wurden die entworfenen Modelle umgesetzt und in der Praxis getestet. Durch den Einsatz moderner Techniken, wie z.B. J2EE und Java, ist eine Software entstanden, die eine Zusammenarbeit mehrerer unterschiedlicher Nutzer mit unterschiedlichen Rechnerplattformen ermöglicht.This work presents results generated during the PRINCE project. PRINCE is an acronym for PRocess INformation and management CEnter. The aim of the project was the support of the design of microsystems with special attention to the technology driven aspects of the design. The technology driven design (design for manufacturing) support is until now only marginally available. Within the project a systematic analysis of the technology driven design was performed. It turns out that a lot of data is accumulated. Also most of the collected data is somehow related. Therefore the organized management of data is a key topic in the design of microsystems. Starting from this realization methods for data management were researched for adequacy. Among the methods known in computer science the relational database was selected. As a result a relational database scheme is presented. All collected data can be stored and related in a useful manner using this scheme. Furthermore an extension of this scheme is presented that enhances it with methods from object oriented modelling. The usage of inheritance and multiple inheritance is discussed in detail. With the PRINCE software a system is presented that puts the model into practical use. Using modern technologies like Java and J2EE the software enables collaborative work among users with different hardware platforms

Bond Strength of a Diatomic Acceptor Ligand: A Reliable Measure of Its Antibond Occupation and Its Charge?

A nitrosyl ligand is bonded to a central metal mainly via a mostly covalent normal bond and a coordinative metal-to-NO pi-backbond. A recent analysis had unravelled similar bonding characteristics of both linear and bent CoNO moieties in terms of ligand charge and antibond occupation. Thus, there should be no justification for the usual assignment of an NO+ ligand to a linear MNO unit and a singlet-NO- ligand to a bent one. This claim seems to contradict that bending an MNO unit weakens the N-O bond with a marked red-shift of the N-O stretch as one indicator. In this work, the failure of Dewar-Chatt-Duncanson-derived conclusions is demonstrated for linear/bent isomer couples by the analysis of M-N and N-O bond strengths. Instead of DCD behavior, lateral electrostatic influence on NO and other diatomic ligands modulates the intraligand bond strength in a similar way as has been shown in former work for polar interaction of a charge with CO in the 'non-classical' carbonyls. Methodologically, local-mode analysis is used to determine bond strengths. Oxidation states are determined by the effective-oxidation-state (EOS) method

Not Guilty on Every Count: The “Non‐Innocent” Nitrosyl Ligand in the Framework of IUPAC′s Oxidation‐State Formalism

Nitrosyl–metal bonding relies on the two interactions between the pair of N–O‐π* and two of the metal's d orbitals. These (back)bonds are largely covalent, which makes their allocation in the course of an oxidation‐state determination ambiguous. However, apart from M‐N‐O‐angle or net‐charge considerations, IUPAC′s “ionic approximation” is a useful tool to reliably classify nitrosyl metal complexes in an orbital‐centered approach

Peatland protection and restoration are key for climate change mitigation

Peatlands cover only about 3% the global land area, but store about twice as much carbon as global forest biomass. If intact peatlands are drained for agriculture or other human uses, peat oxidation can result in considerable CO2 emissions and other greenhouse gases (GHG) for decades or even centuries. Despite their importance, emissions from degraded peatlands have so far not been included explicitly in mitigation pathways compatible with the Paris Agreement. Such pathways include land-demanding mitigation options like bioenergy or afforestation with substantial consequences for the land system. Therefore, besides GHG emissions owing to the historic conversion of intact peatlands, the increased demand for land in current mitigation pathways could result in drainage of presently intact peatlands, e.g. for bioenergy production. Here, we present the first quantitative model-based projections of future peatland dynamics and associated GHG emissions in the context of a 2 °C mitigation pathway. Our spatially explicit land-use modelling approach with global coverage simultaneously accounts for future food demand, based on population and income projections, and land-based mitigation measures. Without dedicated peatland policy and even in the case of peatland protection, our results indicate that the land system would remain a net source of CO2 throughout the 21st century. This result is in contrast to the outcome of current mitigation pathways, in which the land system turns into a net carbon sink by 2100. However, our results indicate that it is possible to reconcile land use and GHG emissions in mitigation pathways through a peatland protection and restoration policy. According to our results, the land system would turn into a global net carbon sink by 2100, as projected by current mitigation pathways, if about 60% of present-day degraded peatlands would be rewetted in the coming decades, next to the protection of intact peatlands

Peatland protection and restoration are key for climate change mitigation

Peatlands cover only about 3% the global land area, but store about twice as much carbon as global forest biomass. If intact peatlands are drained for agriculture or other human uses, peat oxidation can result in considerable CO2 emissions and other greenhouse gases (GHG) for decades or even centuries. Despite their importance, emissions from degraded peatlands have so far not been included explicitly in mitigation pathways compatible with the Paris Agreement. Such pathways include land-demanding mitigation options like bioenergy or afforestation with substantial consequences for the land system. Therefore, besides GHG emissions owing to the historic conversion of intact peatlands, the increased demand for land in current mitigation pathways could result in drainage of presently intact peatlands, e.g. for bioenergy production. Here, we present the first quantitative model-based projections of future peatland dynamics and associated GHG emissions in the context of a 2 °C mitigation pathway. Our spatially explicit land-use modelling approach with global coverage simultaneously accounts for future food demand, based on population and income projections, and land-based mitigation measures. Without dedicated peatland policy and even in the case of peatland protection, our results indicate that the land system would remain a net source of CO2 throughout the 21st century. This result is in contrast to the outcome of current mitigation pathways, in which the land system turns into a net carbon sink by 2100. However, our results indicate that it is possible to reconcile land use and GHG emissions in mitigation pathways through a peatland protection and restoration policy. According to our results, the land system would turn into a global net carbon sink by 2100, as projected by current mitigation pathways, if about 60% of present-day degraded peatlands would be rewetted in the coming decades, next to the protection of intact peatlands.DFG Priority Program “Climate Engineering: Risks, Challenges, Opportunities?” (SPP 1689)Horizon 2020 Framework Programmehttp://dx.doi.org/10.13039/100010661Peer Reviewe

Ultra-compact tunable fiber laser for coherent anti-Stokes Raman imaging

This work describes the construction of an ultra-compact narrowband fiber laser source for coherent anti-Stokes Raman scattering microscopy of Raman tags, that is, for addressing Raman resonances of deuterated molecules and alkyne tags in the spectral range from 2080 to 2220 cm−1. A narrowband and fast electronically tunable cw seed source based on a semiconductor optical amplifier (SOA) emitting around 1335 nm has been employed to seed four-wave mixing (FWM) in an endlessly single mode fiber (ESM) pumped by a ps pulse duration Yb-fiber laser. A conversion efficiency of 50% is demonstrated. This compact fiber optical parametric amplifier (FOPA) has been used to perform coherent anti-Stokes Raman imaging experiments of crystalline deuterated palmitic acid

Impacts of enhanced weathering on biomass production for negative emission technologies and soil hydrology

Limiting global mean temperature changes to well below 2 °C likely requires a rapid and large-scale deployment of negative emission technologies (NETs). Assessments so far have shown a high potential of biomass-based terrestrial NETs, but only a few assessments have included effects of the commonly found nutrient-deficient soils on biomass production. Here, we investigate the deployment of enhanced weathering (EW) to supply nutrients to areas of afforestation-reforestation and naturally growing forests (AR) and bioenergy grasses (BG) that are deficient in phosphorus (P), besides the impacts on soil hydrology. Using stoichiometric ratios and biomass estimates from two established vegetation models, we calculated the nutrient demand of AR and BG. Insufficient geogenic P supply limits C storage in biomass. For a mean P demand by AR and a lowgeogenic-P-supply scenario, AR would sequester 119 Gt C in biomass; for a high-geogenic-P-supply and low-AR-Pdemand scenario, 187 Gt C would be sequestered in biomass; and for a low geogenic P supply and high AR P demand, only 92 GtC would be accumulated by biomass. An average amount of ∼ 150 Gt basalt powder applied for EW would be needed to close global P gaps and completely sequester projected amounts of 190 Gt C during the years 2006-2099 for the mean AR P demand scenario (2-362 Gt basalt powder for the low-AR-P-demand and for the high-AR-P-demand scenarios would be necessary, respectively). The average potential of carbon sequestration by EW until 2099 is ∼ 12 GtC (∼ 0:2-∼ 27 Gt C) for the specified scenarios (excluding additional carbon sequestration via alkalinity production). For BG, 8 kg basaltm2 a1 might, on average, replenish the exported potassium (K) and P by harvest. Using pedotransfer functions, we show that the impacts of basalt powder application on soil hydraulic conductivity and plant-Available water, to close predicted P gaps, would depend on basalt and soil texture, but in general the impacts are marginal. We show that EW could potentially close the projected P gaps of an AR scenario and nutrients exported by BG harvest, which would decrease or replace the use of industrial fertilizers. Besides that, EW ameliorates the soil's capacity to retain nutrients and soil pH and replenish soil nutrient pools. Lastly, EW application could improve plant-Available-water capacity depending on deployed amounts of rock powder - adding a new dimension to the coupling of land-based biomass NETs with EW. © 2020 Royal Society of Chemistry. All rights reserved

Photophysics of Anionic Bis(4H-imidazolato)CuI Complexes

In this paper, the photophysical behavior of four panchromatically absorbing, homoleptic bis(4H-imidazolato)CuI complexes, with a systematic variation in the electron-withdrawing properties of the imidazolate ligand, were studied by wavelength-dependent time-resolved femtosecond transient absorption spectroscopy. Excitation at 400, 480, and 630 nm populates metal-to-ligand charge transfer, intraligand charge transfer, and mixed-character singlet states. The pump wavelength-dependent transient absorption data were analyzed by a recently established 2D correlation approach. Data analysis revealed that all excitation conditions yield similar excited-state dynamics. Key to the excited-state relaxation is fast, sub-picosecond pseudo-Jahn-Teller distortion, which is accompanied by the relocalization of electron density onto a single ligand from the initially delocalized state at Franck-Condon geometry. Subsequent intersystem crossing to the triplet manifold is followed by a sub-100 ps decay to the ground state. The fast, nonradiative decay is rationalized by the low triplet-state energy as found by DFT calculations, which suggest perspective treatment at the strong coupling limit of the energy gap law

Management-induced changes in soil organic carbon on global croplands

Soil organic carbon (SOC), one of the largest terrestrial carbon (C) stocks on Earth, has been depleted by anthropogenic land cover change and agricultural management. However, the latter has so far not been well represented in global C stock assessments. While SOC models often simulate detailed biochemical processes that lead to the accumulation and decay of SOC, the management decisions driving these biophysical processes are still little investigated at the global scale. Here we develop a spatially explicit data set for agricultural management on cropland, considering crop production levels, residue returning rates, manure application, and the adoption of irrigation and tillage practices. We combine it with a reduced-complexity model based on the Intergovernmental Panel on Climate Change (IPCC) tier 2 method to create a half-degree resolution data set of SOC stocks and SOC stock changes for the first 30 cm of mineral soils. We estimate that, due to arable farming, soils have lost around 34.6 GtC relative to a counterfactual hypothetical natural state in 1975. Within the period 1975–2010, this SOC debt continued to expand by 5 GtC (0.14 GtC yr−1) to around 39.6 GtC. However, accounting for historical management led to 2.1 GtC fewer (0.06 GtC yr−1) emissions than under the assumption of constant management. We also find that management decisions have influenced the historical SOC trajectory most strongly by residue returning, indicating that SOC enhancement by biomass retention may be a promising negative emissions technique. The reduced-complexity SOC model may allow us to simulate management-induced SOC enhancement – also within computationally demanding integrated (land use) assessment modeling.</p