A Chemical Route to Monolithic Integration of Crystalline Oxides on Semiconductors

This work demonstrates the growth of crystalline SrTiO₃ (STO) directly on germanium via a chemical method. After thermal deoxidation, the Ge substrate is transferred in vacuo to the deposition chamber where a thin film of STO (2 nm) is deposited by atomic layer deposition (ALD) at 225 °C. Following post‐deposition annealing at 650 °C for 5 min, the STO film becomes crystalline with epitaxial registry to the underlying Ge (001) substrate. Thicker STO films (up to 15 nm) are then grown on the crystalline STO seed layer. The crystalline structure and orientation are confirmed via reflection high‐energy electron diffraction, X‐ray diffraction, and transmission electron microscopy. Electrical measurements of a 15‐nm thick epitaxial STO film on Ge show a large dielectric constant (k ≈ 90), but relatively high leakage current of ≈10 A/cm² for an applied field of 0.7 MV/cm. To suppress the leakage current, an aluminum precursor is cycled during ALD growth to grow crystalline Al‐doped STO (SrTi_1‐x­Al_xO_3‐δ) films. With sufficient Al doping (≈13%), the leakage current decreases by two orders of magnitude for an 8‐nm thick film. The current work demonstrates the potential of ALD‐grown crystalline oxides to be explored for advanced electronic applications, including high‐mobility Ge‐based transistors.     

Voltage fluctuations on distribution level introduced by photovoltaic systems

In moderate climates, short fluctuations in solar irradiance and their impact on the distribution grid will become an important issue with regard to the future large-scale application of embedded photovoltaic systems. Several related studies from the past are recalled. The approach that is presented here applies a localized spectral analysis to the solar irradiance and derived quantities in order to determine the power content of fluctuations, depending on their characteristic persistence. Pseudorandom time series of solar irradiance, based on measured values of the instantaneous clearness index, are applied as input data. Power-flow calculations are carried out in order to assess the impact of fluctuating solar irradiance on the grid voltage. The "fluctuation power index" is defined as a measure for the mean-square value of fluctuations of a specific persistence. A typical scenario is simulated, and the results are interpreted.     

Effect of Carbonaceous Residues on the Blast Furnace Operation Efficiency by PC Injection

Efficiency of pulverized coal (PC) injection determines the coke rate and, consequently, the environmental effect, and depends significantly on its conversion. At high injection rates over 200 kg t_HM⁻¹, a significant part of coal residues, named char, leave the raceway. Char properties and behavior are of great importance in view of their possible consumption outside the raceway. This study continues the investigations of previous works reported in 2020, and comprises numerous laboratory, analytical tests and simulations performed at RWTH Aachen University, as well as industrial measurements. First, the article focuses on the char formation and the temperature development in the raceway while injecting PC. In addition, the effect of alkali on the char reactivity is proven. Next, the effect of injected PC on the pressure drop and permeability in different blast furnace (BF) zones is examined. Also, the char effect on liquid products and the dripping zone is studied. Hot-metal carburization, dynamic and static holdups in the dripping zone, and slag characteristics are investigated. Further available carbonaceous residues in the BF, such as coke fines and soot, are investigated to reveal their competitive consumption. Finally, a method for identification and quantification of carbon phases in BF dust is developed.     

Mehrfunktionelle N-Tenside. I. Nucleophile Substitutionen an Bischlornitrosoverbindungen 2. Reaktionen mit Thioharnstoff,substituierten Thioharnstoffen,Salzen und Estern von Dithiocarbaminsäuren und Mercaptoheterocyclen [1]

Polyfunctionalized N-Tensides. I. Nucleophilic Substitutions with Bischloronitroso Compounds. 2. Reactions with Thiourea, Substituted Thioureas, Salts and Esters of Dithiocarbamic Acid and Mercaptoheterocyclic Compounds Reaction of bischloronitroso compounds 1 with thiourea and substituted thioureas gives 2-aminothiazoles and 3-alkyl-2-iminothiazolines-(4). Ammoniumdithiocarbamate formes 4-thiazolinethiones-(2), and esters of the dithiocarbamic acids give 2-alkylmercaptothiazoles. N-substituted salts of dithiocarbamic acid and mercaptoheterocyclics react in boiling ethanol to form S-(β-oximinoalkyl)-dithiocarbamates 8 and in some cases 4-thiazolinthiones-(2) 9 .     

Formulation lyotropic liquid crystals from palm oil-based monoacylglycerols

Lyotropic liquid crystals (LLCs) made of monoacylglycerols (MAGs) are rich in potential for food and pharmaceutical applications but the understandings of these materials are quite limited. This study, therefore, precisely demonstrated the formation of some LLCs based on the combination of two palm oil-based MAGs (distilled and non-distilled) with water and a triblock copolymer (Pluronic F127). X-ray diffraction results showed that the main lyotropic mesophase obtained from palm oil-based MAGs was lamellar phase (L_α) while dynamic light scattering results revealed that these LLC particles had a size range from 0.5 to 4 μm (after 5 min homogenization at 12,000 rpm). LLC dispersions made of both palm oil-based MAGs/water mixtures were shear-thinning fluids and the sample owning a higher concentration of MAGs had a higher yield stress as well as a higher storage modulus.