A note on the St. Petersburg paradox

((Without abstract.))     

SnO2 quantum dots decorated BiOI nanoflowers as a high-performance electrode material for supercapacitor application

Journal of Solid State Electrochemistry - The rational design of low-cost electrode materials with superior redox activity and high electrochemical conductivity has attracted extensive interest for...     

Self-Driven Prenucleation-Induced Perovskite Crystallization Enables Efficient Perovskite Solar Cells

Perovskite film with high crystal quality is fundamental to achieving high-performance solar cells. A fast nucleation process is crucial to improving the crystallization quality. Here, we propose a self-driven prenucleation strategy to achieve fast nucleation. This is realized through rational solvent design. The key characteristics of different solvents are systematically evaluated. Among them, formamide, with ultra-high dielectric constant, low Gutman donor number, and a high boiling point, is selected as the co-solvent. These unique characteristics render formamide a double-face solvent that is a good solvent for formamidinium iodide (FAI) and CsI while a poor solvent for PbI₂. As a result, formamide induces the self-driven prenucleation of PbI₂-DMSO seeding crystals and accelerates the nucleation, improving the crystalline quality of perovskite film. The efficiency of the hole transport layer-free carbon-based perovskite solar cells is boosted beyond 19 % for the first time.     

Isotope shifts in the second negative bands of O 2 +

The second negative bands of O ₂ ⁺ , lying in the region 5000–1850 Å, have been photographed using oxygen enriched in¹⁸O. A study of the isotope shifts in the band heads revealed that thev″ numbering is to be increased by one unit whereas thev′ numbering remains unaltered. This change in vibrational numbering leads to a revision of the molecular constants of O ₂ ⁺ , especially of those in its ground state. These are discussed and the extension of the band system in the vacuum ultra-violet region reported. The possibility of developing a simple spectrographic method for the isotopic assay of oxygen using the isotope shifts in this band system is pointed out. The revised rotational and vibrational constants in theX ² II _g ground state of O ₂ ⁺ molecule are as follows :

$$\begin{gathered} \omega _e = 1903 \cdot 85 cm.^{ - 1} , \hfill \\ \omega _e x_e = 16 \cdot 18 cm.^{ - 1} , \hfill \\ B_e = 1 \cdot 6920 cm.^{ - 1} \hfill \\ and \hfill \\ r_e = 1 \cdot 1161 {\AA}. \hfill \\ \end{gathered} $$     

Synthesis and antibacterial activity of a new series of 2,3,5,7-substituted-pyrido[2,3-d]pyrimidin-4(3h)-one derivatives

A new series of 2,3,5,7-substituted-pyrido[2,3-d]pyrimidin-4(3H)-one derivatives were prepared from 2-amino-N,6-substituted phenyl-4-(trifluoromethyl or methyl)nicotinamides. The key intermediate 2-amino-N,6-substituted phenyl-4-(trifluoromethyl or methyl)nicotinamides were synthesized from 2-bromo-N,6-disubstituted phenyl-4-(trifluoromethyl or methyl)nicotinamides as well as from ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) coupling of 2-amino-4,6-substituted nicotinic acid and substituted arylamines. All the synthesized compounds were screened for antibacterial activity against Gram +ve and Gram -ve bacteria. Compound 7c showed better antibacterial activity against Gram +ve and Gram -ve bacteria.     

Physico-chemical properties of pure and x-ray irradiated single crystals of KAP

Single crystals of potassium hydrogen phthalate (KAP) have been grown by slow evaporation method from aqueous solutions. Thermal analyses indicate that KAP crystals decompose into phthalic anhydride and KOH around 520 K. Electrical properties of single crystals of KAP have been studied along with the effect of X-ray irradiation of the crystals. The electrical transport appears to be associated with tunneling of protons. The irradiated crystal exhibits lower dielectric constant and higher ac conductivity.     

The Resonant Wave Numbers of Eccentric Ring Microstrip Antennas for All Modes

The method, connected with the concentric ring microstrip antenna and based on the perturbation , for the resonant wave numbers of eccentric ring microstrip antennas for all modes is suggested. The usefulness and accuracy of the method is shown through the comparison of the calculation used here with the measurement and other method from the reference.