АВТОМАТИЧЕСКАЯ ИЗМЕРИТЕЛЬНАЯ ИНФОРМАЦИОННАЯ СИСТЕМА ДЛЯ ИССЛЕДОВАНИЯ РАЗРЫВНЫХ И ПЛАВНО ИЗМЕНЯЮЩИХСЯ ТЕЧЕНИЙ

The purpose of the paper is to present an automatic Measuring Information System (MIS) which has been developed at the BNTU in collaboration with the BSU and demonstrate its application in experimental investigations of kinematics and dynamics of discontinuous and smoothly changing flows, particularly, for more complete account of dynamic wave action on objects located in the hydraulic construction downstream.Цель статьи – представить созданную в БНТУ совместно с БГУ автоматическую измерительную информационную систему (ИИС) и ознакомить с возможностями ее применения в экспериментальных исследованиях кинематики и динамики разрывных и плавно изменяющихся течений, в частности для более полного учета динамического воздействия волн на объекты в нижних бьефах гидросооружений

ЭКСПРЕСС-МЕТОДИКА БЕСКОНТАКТНОГО ИЗМЕРЕНИЯ ЭЛЕКТРИЧЕСКИХ ПАРАМЕТРОВ НЕБОЛЬШИХ ОБРАЗЦОВ НА СВЕРХВЫСОКИХ ЧАСТОТАХ

The setup with a reflective microwave H101 resonator for the non-contact measurements of the electrical parameters of compact samples (the diameter less than 5 mm) is constructed. An analytical expression for calculation of the microwave power reflection coefficient by the H101 resonator with the sample being inside the resonator with respect to the dielectric permittivity and conductivity of sample is obtained. The dependence of the microwave power reflection on the diameter of the metallic and glassy globs freely falling through the resonator is experimentally found. an>Разработана установка с  отражательным  СВЧ-резонатором  типа  H101 для  бесконтактного измерения электрических параметров небольших (диаметром ≤ 5 мм) образцов. Получено аналитическое выражение для расчета коэффициента отражения мощности СВЧ-излучения H101-резонатором с находящимся в нем образцом в зависимости от диэлектрической проницаемости и электропроводности образца. Экспериментально найдена зависимость отражения СВЧ-мощности от диаметра металлических и стеклянных шариков при их свободном падении через резонато

Structural dependence of the efficiency of functionalization of silica-coated FeOx magnetic nanoparticles studied by ATR-IR

The efficiency of propylamino functionalization of magnetic silica-coated FeOx nanoparticles prepared by different methods, including coprecipitation and flame aerosol synthesis, has been evaluated by attenuated total reflection infrared spectroscopy (ATR-IR) combined with a specific surface reaction, thus revealing the availability of the grafted functional groups. Large differences in the population of reactive groups were observed for the investigated materials, underlining the tight relation between the structure of nanoparticles and their suitability for organic functionalization. The materials possessed different core structure, surface area, and porosity, as evidenced by transmission electron microscopy and nitrogen adsorption–desorption isotherms. Grafting of aminopropyl groups using a standard procedure based on reaction with (3-aminopropyl)trimethoxysilane as source of the propylamino groups was performed, followed by classical dry analysis methods to determine the specific concentration of the organic functional groups (in mmol g−1 of material). ATR-IR spectroscopy in a specially constructed reactor cell was applied as wet methodology to determine the chemically available amount of such functional groups, showing that the materials possess largely different loading capacity, with a variability of up to 70% in the chemical availability of the organic functional group. The amount of (3-aminopropyl)trimethoxysilane used for functionalization was optimized, thus reaching a saturation limit characteristic of the material

FAST METHOD OF NON-CONTACT MICROWAVE MEASUREMENTS OF ELECTRICAL PARAMETERS OF COMPACT SAMPLES

The setup with a reflective microwave H101 resonator for the non-contact measurements of the electrical parameters of compact samples (the diameter less than 5 mm) is constructed. An analytical expression for calculation of the microwave power reflection coefficient by the H101 resonator with the sample being inside the resonator with respect to the dielectric permittivity and conductivity of sample is obtained. The dependence of the microwave power reflection on the diameter of the metallic and glassy globs freely falling through the resonator is experimentally found. an&gt

Electronic spectra of C6H+ and C6H3+ in the gas phase

Measurement of the Π3−Π3 transition of C6H+ in the gas phase near 19486 cm−1 is reported. The experiment was carried out with a supersonic slit-jet expansion discharge using cavity ringdown absorption spectroscopy. Partly resolved P lines and observation of band heads permitted a rotational contour fit. Spectroscopic constants in the ground and excited-state were determined. The density of ions being sampled is merely 2 × 108 cm−3. Broadening of the spectral lines indicates the excited-state lifetime to be ≈100 ps. The electronic transition of HC6H2+ at 26402 cm−1 assumed to be A11−X 1A1 in C2v symmetry could not be rotationally resolved

Acute phenylalanine/tyrosine depletion of phasic dopamine in the rat brain

RATIONALE: Dopamine plays a critical role in striatal and cortical function, and depletion of the dopamine precursors phenylalanine and tyrosine is used in humans to temporarily reduce dopamine and probe the role of dopamine in behavior. This method has been shown to alter addiction-related behaviors and cognitive functioning presumably by reducing dopamine transmission, but it is unclear what specific aspects of dopamine transmission are altered. OBJECTIVES: We performed this study to confirm that administration of an amino acid mixture omitting phenylalanine and tyrosine (Phe/Tyr[-]) reduces tyrosine tissue content in the prefrontal cortex (PFC) and nucleus accumbens (NAc), and to test the hypothesis that Phe/Tyr[-] administration reduces phasic dopamine release in the NAc. METHODS: Rats were injected with a Phe/Tyr[-] amino acid mixture, a control amino acid mixture, or saline. High-performance liquid chromatography was used to determine the concentration of tyrosine, dopamine, or norepinephrine in tissue punches from the PFC and ventral striatum. In a separate group of rats, phasic dopamine release was measured with fast-scan cyclic voltammetry in the NAc core after injection with either the Phe/Tyr[-] mixture or the control amino acid solution. RESULTS: Phe/Tyr[-] reduced tyrosine content in the PFC and NAc, but dopamine and norepinephrine tissue content were not reduced. Moreover, Phe/Tyr[-] decreased the frequency of dopamine transients, but not their amplitude, in freely-moving rats. CONCLUSIONS: These results indicate that depletion of tyrosine via Phe/Tyr[-] decreases phasic dopamine transmission, providing insight into the mechanism by which this method modifies dopamine-dependent behaviors in human imaging studies

Regional Variation in Phasic Dopamine Release during Alcohol and Sucrose Self-Administration in Rats

ABSTRACT: While dopamine input to the dorsal striatum is well-known to be critical for action selection, including alcohol-motivated behaviors, it is unknown whether changes in phasic dopamine accompany these behaviors. Long-term alcohol abuse is believed to promote alterations in the neurocircuitry of reward learning in both ventral and dorsal striatum, potentially through increasing dopamine release. Using fast-scan cyclic voltammetry, we measured phasic dopamine release in the dorsal and ventral striatum during alcoholic and nonalcoholic reward-seeking behavior and reward-related cues in rats trained on a variable-interval schedule of reinforcement. We observed robust phasic dopamine release in the dorsolateral striatum after reinforced lever presses and inconsistent dopamine release in the dorsomedial striatum. Contrary to our expectations, alcohol did not enhance dopamine release in rats drinking alcoholic rewards. Cue-induced dopamine release was also observed in the nucleus accumbens core of rats drinking the reward solutions. These data demonstrate that alcoholic and nonalcoholic reward self-administration on a variable-interval schedule of reinforcement in rats is accompanied by phasic dopamine release time-locked to reinforcement in the dorsolateral striatum and the nucleus accumbens, but not the dorsomedial striatum