Study of effect of Sn doping of EuBa2Cu3-xO7-δ compound on superconducting properties by contactless methods

Effect of Sn addition on structural and superconducting properties in EuBa2Cu3O7-δ (Eu-123) compound was studied using XRD and SQUID magnetometric measurements. Transition process from normal to superconducting state was analyzed by the measurement of temperature change of the magnetic moment of the combined ZFC and the remanence technique beside the usual ZFC and FC ones. Samples of the nominal composition EuBa2Cu3-xSnxO7-δ with x ranging from 0.0 to 0.2 were prepared by the solid state reaction technique from Eu2O3, BaCO3, CuO and SnO2 precursors. The increasing Sn-content deteriorates the superconducting properties of the Sn doped samples

Smart weather forecast

Táto bakalárska práca sa zaoberá tvorbou algoritmu automaticky generovaných textov a ich konkrétnym využitím v počítačových predpovediach počasia. Je zameraná na zber poznatkov v spomenutých oblastiach a tiež rieši problematiku softvéru, ktorý bol použitý na dosiahnutie vytýčených cieľov. Prvá časť pojednáva o histórii vývoja digitálneho generovania a jeho využití v súčasnosti. Vymedzuje hlavné pravidlá a metódy potrebné pre zostrojenie podobného programu. Taktiež sa venuje zhromaždeniu potrebných informácií pre zostrojenie vlastnej meteorologickej stanice a opisuje dôležité vlastnosti softvéru, ktorý môže byť pri takomto procese použitý. Nakoniec, s ohľadom na rešerše vytvorené v predchádzajúcich kapitolách, opisuje postup tvorby vlastného programu, ktorý dokáže získať informácie o predpovedi počasia, spracovať ich a následne odoslať a zdieľať na sociálnej sieti Twitter.This bachelor thesis focuses on the creation of an algorithm of automatically generated texts and their particular application in computer weather forecasts. It is aimed at gathering information from the fields mentioned above as well as about in the sphere of the software used to reach the set goals. The first part regards the history of development of digital generating and its present-day use. It specifies main rules and methods necessary to design such a programme. It also deals with the accumulation of required information for the designing of its own meteorological station and describes important features of the software, which can be used in such a process. Lastly, it also describes the creation of a programme which is able to gain and process information about weather forecasts and subsequently share them on social platform Twitter, all in consideration with the researches in previous chapters.

Identification of single-domain structures in the system YBa 2 Cu 3 O 7-δ -Ag by magnetization measurements

Abstract The magnetization methods were used in study of effect of Ag doping on the structural and superconducting parameters in two series of melted and highly textured samples of the system (YBa 2 Cu 3 O 7−δ ) 1-x (Ag 2 O) x . The x concentration level of the first series ranged from 0 to 10 wt % and the second one from 0 to 3.6 wt % Ag 2 O. By means of the SQUID magnetization measurements the optimum Ag 2 O doping level ranged from 1.6 to 2.8 wt %. These methods led to optimization of conditions in preparation of single-domain samples. From the secondary precipitated CuO phase and from the appearance of Ag component the solubility limit of Ag in solid solution YBa 2 Cu 3−y Ag y O 7−y/2−δ was found

Front Cover: Enhancing the Potential of Fused Heterocycle‐Based Triarylhydrazone Photoswitches (Chem. Eur. J. 8/2024)

A new class of triarylhydrazone photoswitches has been designed, following an idea to control the strength of a hydrogen bond connecting the photo-active hydrazone part with a heteroaryl substituent. Introducing a benzothiazole moiety results in high thermal stability, absorption above 365 nm, and satisfactory photoconversion rates. High-quality calculations and advanced ultrafast spectroscopy allowed the nature of the electronic transitions to be resolved and the photoisomerization mechanism to be elucidated

Enhancing the Potential of Fused Heterocycle-Based Triarylhydrazone Photoswitches

Triarylhydrazones represent an attractive class of photochromic compounds offering many interesting features including high molar absorptivity, good addressability, and extraordinary thermal stability. In addition, unlike most other hydrazone-based photoswitches, they effectively absorb light above 365 nm. However, previously prepared triaryhydrazones suffer from low quantum yields of the Z→E photoisomerization. Here, we have designed a new subclass of naphthoyl-benzothiazole hydrazones that balance the most beneficial features of previously reported naphthoyl-quinoline and benzoyl-pyridine triarylhydrazones. These preserve the attractive absorption characteristics, exhibit higher thermal stability of the metastable form than the former and enhance the rate of the Z→E photoisomerization compared to the later, as a result of the weakening of the intramolecular hydrogen bonding between the hydrazone hydrogen and the benzothiazole moiety. Introducing the benzothiazole motif extends the tunability of the photochromic behaviour of hydrazone-based switches.</p

Effects of Ru Addition on the Superconducting Properties of the Eu-123 System

Effects of the Ru addition on the structural and superconducting properties of the Eu-123 system were studied. Samples of the nominal composition $EuBa₂Cu_{3-x}Ru_{x}O_{7-δ}$ with x ranging from 0.0 to 0.7 were prepared by the solid state reaction technique from Eu₂O₃, BaCO₃, CuO and RuO₂ precursors at the temperature of 1050°C for 72 h in flowing oxygen and oxygen-annealed at 580°C for 24 h. X-ray diffraction data show the presence of another Ba-Eu-Ru-O phase, for x ≥ 0.03, in addition to the main superconducting phase. AC and DC magnetization characteristics were measured by the compensation method using the second-order SQUID gradiometer at ≈ 77 K and the QD SQUID magnetometer MPMS XL-7 at 20 K. The superconducting properties, $T_{c}$, $ΔT_{c}$, change only weakly up to x = 0.2, and magnetization M(H) deteriorates with an increasing Ru content

Effects of Europium-Barium Nonstoichiometry in EBCO123 Systems on Transition and Magnetization Properties

We studied the effects of Eu-Ba nonstoichiometry in two series of $Eu_{1+x}Ba_{2-x}Cu_3O_{7-δ}$ and $Eu_{1-x}Ba_{2+x}Cu_3O_{7-δ}$ samples on transition, structural, and magnetic properties. The samples with the nominal composition of 0≤x≤0.07 were synthesized by the solid-state reaction method from $Eu_2O_3,$ $BaCO_3,$ and CuO precursors and sintered at 1050°C for 72 h in flowing oxygen. All the samples show the values of critical temperature $T_c$, volume density ρ, and maximum volume magnetization $M_\text{max}$ higher than 90 K, 6.3 g $cm^{-3}$ and $10^4 Am^{-1}$, respectively, except for x = 0.07 samples. The Eu-Ba nonstoichiometry in the two series shows different effects on transport, magnetization hystereses, and intergrain properties of the samples