Electrical Properties of Mn3−xCoxO4 (0 ≤ x ≤ 3) Ceramics: An Interesting System for Negative Temperature Coefficient Thermistors

Single‐phase spinel manganese cobalt oxides Mn_3?xCo_xO₄ dense ceramics were prepared for the first time and their structural/electrical property relationships characterized. The electrical properties, that is, the resistivity at 25°C, the energetic constant, and the resistance drift at 125°C, were determined and correlated with the cation distribution. Finally, the electrical characteristics of the Mn_3?xCo_xO₄ system were compare'd with other important classes of manganese‐based spinel oxides, Mn_3?xNi_xO₄ and Mn_3?xCu_xO₄, already commercialized as negative temperature coefficient (NTC) thermistors. The high values of energetic constant and low resistivities observed in Mn_3?xCo_xO₄ ceramics present a promising interest for such industrial applications.     

Low-Temperature Creep of Nanocrystalline Titanium(IV) Oxide

Nanocrystalline TiO₂ with densities higher than 99% of rutile has been deformed in compression without fracture at temperatures between 600° and 800°C. The total strains exceed 0.6 at strain rates as high as 10⁻³ s⁻¹. The original average grain size of 40 nm increases during the creep deformation to final values in the range of 120 to 1000 nm depending on the temperature and total deformation. The stress exponent of the strain rate, n , is approximately 3 and the grain size dependence is d ^{− q} with q in the range of 1 to 1.5. It is concluded that the creep deformation occurs by an interface reaction controlled mechanism.     

Synthetic MUC1 Antitumor Vaccine with Incorporated 2,3‐Sialyl‐T Carbohydrate Antigen Inducing Strong Immune Responses with Isotype Specificity

The endothelial glycoprotein MUC1 is known to underlie alterations in cancer by means of aberrant glycosylation accompanied by changes in morphology. The heavily shortened glycans induce a collapse of the peptide backbone and enable accessibility of the latter to immune cells, rendering it a tumor‐associated antigen. Synthetic vaccines based on MUC1 tandem repeat motifs, comprising tumor‐associated 2,3‐sialyl‐T antigen, conjugated to the immunostimulating tetanus toxoid, are reported herein. Immunization with these vaccines in a simple water/oil emulsion produced a strong immune response in mice to which stimulation with complete Freund's adjuvant (CFA) was not superior. In both cases, high levels of IgG1 and IgG2a/b were induced in C57BL/6 mice. Additional glycosylation in the immunodominant PDTRP domain led to improved binding of the induced antisera to MCF‐7 breast tumor cells, compared with that of the monoglycosylated peptide vaccine.     

Characterization and optimization of a bipolar ESD-device by measurements and simulations

The design of ESD (electro-static discharge) protection structures can be significantly shortened by using thermo-electrical device simulations. In many cases simulation results predict the performance of new designs enough accurate which makes it unnecessary to go through the whole manufacturing process of test chips. More important, however, they allow the designer to gain additional insight into a problem by examining device-internal parameters that are not obtainable through measurements, such as current densities, the electric field and the lattice temperature. In this article we investigate and optimize a p-base type npn-transistor with a vertical and a lateral operation mode. Based on the TCAD tool chain, we develop a methodology to simulate the transient switching behavior, the avalanche breakdown and the snapback holding voltages of the device. To validate our design methodology we implemented the evaluated devices on a real test chip which has also been used to gain the needed data for the calibration of the simulators. Thus we are able to compare simulation and measurements and found the simulated voltages to closely match values obtained in measurements. In addition we extracted a set of parameters for a compact circuit model describing the device under various ESD stress types.     

Experiences on reliability simulation in the framework of the PROPHECY project

Electromigration and oxide time dependent dielectric breakdown simulations based on library elements of a 0.35 μm CMOS technology have been performed. In the case of hot carrier degradation simulations as well as experiments using 99-stage ring oscillators of the same 0.35 μm CMOS technology have been carried out and compared. The frequency behaviour as a function of supply voltage and temperature has been investigated. Relaxation effects on the ring oscillators have been found. These effects are not covered by the reliability simulation tool. In a certain region of supply voltage and operation time the results of simulations could be confirmed by experiments. In all other cases the measured frequency degradation was smaller than the simulated degradation.     

Flexibler Betrieb von Luftzerlegungsanlagen

As part of the Energiewende, the current research on energy-optimized, flexible operation of air separation units is described. A realistic, pressure-driven approach for dynamic simulation is presented, which is used to provide a detailed, transient simulation model, a digital twin, of an air separation unit. Extreme operation scenarios, such as start-up and shutdown of the main heat exchanger, the distillation columns or the entire air separation unit, are described. Since the main heat exchanger experiences repeated temperature changes, its lifetime is investigated in a test rig. The gathered data is used to derive and validate three dimensional simulation models.     

Crystalline Parts of Three Different Conformations Detected in Native and Enzymatically Degraded Starches

We examined cereals and legume starches with different amylose contents, using X-ray wide-angle scattering. The parts of polymorphs in the crystalline regions and the crystallinity of the starches were determined. The high-amylose starches hold 74.6%-84.6% B-type and 15.4%-22.6% VH-type. Crystallinity of high-amylose starches is xc = 0.154–0.17. According to phase analysis of the scattering curve of wheat starch 6.8% B-type and 93.2% A-type are contained. Thus, in the crystalline phase wheat starch is more heterogeneous than maize starch. The residuary substance of heterogeneous hydrolysis of wheat starch at T1 =58°C is an insoluble sediment, which does contain already 17.1 % VH-Amylose. This is the proof of the amylose-lipid complex in the sediment. If the temperature of hydrolysis raised to 70°C, the VH,-amylose proportion increased to 80.5%. Since the crystalline VH- structures are detectable during heterogeneous hydrolysis as from T1 = 58°C, they seem to have contained already in native starch.     

Hydrothermische Behandlung von Stärke in Gegenwart von α-Amylase Teil 2: Einfluß einer hydrothermischenzymatischen Modifizierung auf die Quellungstemperatur von Weizenstärken

Hydrothermal Treatment of Starch in the Presence of α-Amylase. Part 2: Effect of a Hydrothermal Enzymatic Modification on the Swelling Temperature of Wheat Starches. The hydrothermal treatment of wheat starch in the presence of bacterial-α-amylase is directed to the production of modified residual starches with a maximal shift of swelling temperature T_max (measured by DSC) at high yields. The annealing of granular starch at temperatures below the swelling temperature (50°C) in presence of α-amylase gives no difference regarding the shift of T_max. Because of the hydrolysis of swollen material it is possible to use higher reaction temperatures and the process becomes more effective. The formed maltose syrup retards the shift of T_max and protects the granules. Within 24h wheat starch can be modified with a yield of 70% and a shift of T_max of 8K.     

Über Gesetzmäßigkeiten in der π-Elektronenstruktur von heteroanalogen Polyvinylidenverbindungen

On Regularities of the π-Electronic Structure of Heteroanalogous Polyvinylidene Compounds Starting with simple forms of the equations for the eigenvalues and eigencoefficients of the π-system of heteroanalogous polyvinylidene compounds 3 several regularities in the π-electronic structure of these systems are derived and compared with known experimental facts. In this line several predictions are given for the properties of compounds unknown up to now.