Direct growth of copper(I) oxide nanocubes on graphitic carbon nitrides enhancing aqueous carbon dioxide photoreduction

Semiconductor hybrid structures containing multiple components have been considered an ideal photocatalyst design to generate long-lived charge-separated states. Particularly for the reactions requiring high activation energies, such as a CO2 reduction reaction (CO2RR), the reaction activity is highly susceptible to the catalyst component and morphology. In this study, we selected g-C3N4 and Cu2O as photocatalytic components having bandgaps suitable for CO2RR. Then, we tried to form good electric junctions between two domains by direct growth of Cu on g-C3N4 using a polyol process. The resulting g-C3N4/Cu2O hybrid was employed as photocatalysts in an aqueous medium without hole acceptors. The catalyst exhibited a noticeable activity (5.4 mmol gcat-1h-1) and quantum yield (3.7%) with a nearly quantitative selectivity for CH4 production, superior to any other photocatalysts for CO2RR. The strong coordination of g-C3N4 to the Cu2O surface could form a conductive junction and induce effective electron transfer enforcing the Z-scheme process for CO2RR in high activity and selectivity. This result ensured the importance of junctions and interfaces in the hybrid catalyst structure to exhibit excellent photocatalytic CO2RR performances.

Investigation of the plasma composition of a discharge with a self-heating hollow cathode and an active anode in a gas mixture with titanium and hexamethyldisilazane vapors

The analysis of composition of low-pressure (~0.1-1 mTorr) hollow cathode arc plasma in Ar+N2 gas mixture with Ti+hexamethyldisilazane vapors was carried out by optical emission spectroscopy. The influence of HMDS flow rate (1-10 g/h), discharge current (10-50 A) and Ti-vapors flow on hexamethyldisilazane decomposition degree and plasma composition and was investigated. The proposed plasma activation method provides both an intense flow and a high activation degree of metal vapors, and a sufficient decomposition degree of precursor vapors for the formation of solid TiSiCN coatings at a high deposition rate. Test coatings with a thickness of 6 microns and a hardness of 31 GPa were obtained in 1 hour at 400ºC.

Rheological Characterization and Modeling of Thermally Unstable Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)

Presently, almost every industry uses conventional plastics. Its production from petroleum and extensive plastic pollution cause environmental problems. More sustainable alternatives to plastics include bioplastics such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), which is produced by bacteria and is biodegradable even in seawater. High temperature sensitivity as well as massive thermal degradation cause difficulties during the processing of PHBV. The aim of this work is to create a detailed rheological characterization and master curves to gain deeper knowledge about the material and its processing parameters. The rheological characterization was performed with frequency sweeps in the range of 0.1 rad/s to 628 rad/s and time sweeps over 300 s. Creating master curves at the reference temperature of 180 °C with the software IRIS delivers Carreau and Arrhenius parameters. These parameters allow for a calculation of the master curves for all other temperatures by means of the temperature shift factor. Moreover, the rheological measurements reveal a minimum rheological measurement temperature of 178 °C and a surprisingly high activation energy of 241.8 kJ/mol.

A comprehensive study of indole catalytic hydrodenitrogenation under hydrothermal conditions

This article focuses on the catalytic hydrodenitrogenation (HDN) mechanism of indole under hydrothermal conditions. Both gaseous hydrogen and liquid hydrogen donor formic acid (FA) can improve indole conversion and total yield of denitrogenated products. Ru/C showed the highest activity among the catalysts for indole conversion in all temperature conditions with the existence of H2 and 91.17 % indole was converted at 400 °C and 60 min. Based on reaction kinetic experiments, a kinetic model was developed to describe the hydrothermal HDN reaction of indole over the home-made Ni80Ru20/γ-Al2O3 catalyst, which clearly captured all data trends and fitted the temporal variation of all major liquid products. High activation energy for formation of O-containing substance o-cresol from both mathematical fitting and density functional theory (DFT) calculation indicated a rare occurrence of reaction between pyrrole ring-opening product methyl aniline and H2O, consistent with experimental observation that only a trace of o-cresol was detected.

Individual-psychological features of law enforcement officers with different professional experience and professional profile

The study of professionally significant individual-psychological features of employees of law enforcement units in relation to the leading type of activity, including taking into account professional experience, is an actual scientific and practical issue. The identification of the requirements of the profile activity imposed on the employee, the assessment of different-level individual-psychological qualities allows to draw a conclusion about the effectiveness and suitability of the employee for the profession. The professional experience of employees of law enforcement agencies significantly affects the features of stress response, decision-making, motives for official activity, and the state of maladjustment. The study aims to identification of individual-psychological characteristics of law enforcement officers with different profiles and professional experience. 179 male law enforcement officers (average age - 30,2±6,2 years, average professional experience - 7,5±6,1 years) were examined. The employees were divided into 3 groups, depending on the type of professional activity. Group 1 consisted of employees of the security profile (n=67), group 2 - of the communicative-informational profile (n=46), group 3 - of the inspector-communication profile (n=66). The subjects were further divided into subgroups with professional experience up to 9 years inclusive and with experience of 10 or more years. The methodological complex includes: Self-control questionnaire; Behavior Activation and Inhibition questionnaire; Test Technology of Psychosemantic Analysis - Semantic Analysis of Activity (Noss I.N., 2009); Test Problem Situation Analysis (Noss I.N., 2009); a modification of the S. Rosenzweig Frustration Toleration Test (Noss I.N., Ignatkin V.N., 1997). The employees of the security profile were distinguished by the predominance of intropunitive reactions and fixation on the obstacle when assessing the conflict from their own position, high physical activity. Individuals of the communicative-informational profile were distinguished by impunitive reactions, fixation on self-defense and satisfaction of needs, high inhibition of behavior to negative stimuli, high activation of behavior, and high efficiency of resolving problem situations when assessing the conflict from an external position. Persons of the inspector-communication profile were distinguished by high rates of extrapunitive reactions in the whole, unrestrained affect of irritation, preference for simple tasks, low inhibition of behavior. The classification in a group of the security profile with high professional experience contribute: a preference for simple tasks, high activation to promote; in the group of communicative-informational and inspector-communication profile - high activation of achieving the goal. The generalized group of law enforcement officers with 10 years or more of experience in assessing the conflict from their own position was distinguished by the severity of extrapunitive reactions and fixation on the obstacle and on self-defense, the predominance of unrestrained affect of irritation, preference for simple tasks, low inhibition of behavior to negative stimuli. The results obtained allow us to conclude that there are differences in the psychological profile of law enforcement officers with different types of official activities and work experience. The profile of employees of communication-information activities was more consistent with the universal personal and professional qualities required for employees of law enforcement agencies in terms of psychophysiological qualities. Least consistent with a universal professional requirements officers of inspector-communication activities, which was reflected in low capacity for learning, reducing the effectiveness of problem-solving, emotional instability. With an increase in the length of professional experience, there is a predominance of externally blaming response strategies and low self-control.

Dielectric Properties Bi₂MgTaNbO₉

A phase-pure mixed oxide of the composition Bi2MgNbTaO9 with a pyrochlore structure was obtained by the ceramic synthesis method. The sample was characterized by the methods of X-ray phase and EDS analyzes, electron scanning microscopy. The electrical properties of samples of different thicknesses were investigated by impedance spectroscopy. The unit cell parameter is a = 1.0544 nm (sp. gr. Fd3m). As a result of modeling the impedance hodographs, an equivalent circuit is proposed that satisfactorily describes the electrical behavior of the sample. Bi2MgNbTaO9 is characterized by a high activation energy of 1.28 eV; moderately high dielectric constant ~62–71 and dielectric loss tangent ~0.003 at 1 MHz and 18 °С. No ionic transfer was detected. The investigated ceramics can be used to create multilayer ceramic capacitors

A light-activatable antibiotic with high activation efficiency and uncompromised bactericidal potency in the activated state

Achieving activatable antibiotics represents one promising solution to tackle the occurrence of side effects, one major issue now plaguing antibiotic usage in collagen-based biomaterials. Despite considerable effort, however, rationale design of activatable antibiotics that display high activation efficiency and uncompromised bactericidal potency in the activated state remains difficult. Here, we demonstrate a design principle that helps to address this challenge. This strategy differs from previous attempts by underscoring photolytic removal of a functionality directly conjugated to the pharmacophore of an antibiotic, enabling not only an activation efficiency significantly improved beyond previous light-activatable antibiotics, but also bactericidal activity in the activated state as potent as the parent drug. Graphical abstract