Synthesis and characterization of poly(N-propionyl)iminoethylene

Summary The cationic polymerization of 2-ethyl-2-oxazoline using CH₃I as initiator at different monomer/initiator ratios, temperatures, solvents and times of polymerization was carried out. The effect of these variables on the polymerization yield and viscosity of the polymers was studied. The poly(N-propionyl)iminoethylene was hydrolyzed in acid medium obtaining a linear poly(ethyleneimine) (PEI). All the polymers were characterized by elemental analysis, IR,¹H NMR, and¹³C NMR spectroscopy.     

Reactivity of platinum nanoaggregates in catalytic reduction of U(VI) with hydrazine in acid solutions

Catalysts Pt/SiO₂ with different size of Pt nanoaggregates were studied in catalytic reduction of U(VI) with hydrazine in solutions of H₂SO₄, HClO₄, and HNO₃. The catalytic activity of the surface Pt atoms of Pt/SiO₂ in this reaction monotonically increases with an increase in the size of metal crystallites on the support, i.e., the negative size effect is observed. Catalytic reduction of U(VI) with hydrazine in H₂SO₄ solutions is significantly faster than in HClO₄ and HNO₃, and in HClO₄ it is slightly faster than in HNO₃. The results were interpreted within the framework of the concept of the energetic nonuniformity of the surface atoms and of the mechanisms of catalytic reduction of U(VI) with hydrazine in acid solutions.     

Distributions of multi-estimates for multistage stochastic inclusions

The problems of constructing recursive relations for conditional and unconditional distributions of random informational sets are considered. These sets, which are called multi-estimates in the paper, appear naturally in the problems of estimation of states and parameters of multistage stochastic inclusions.     

Selective control of the observables in the ensemble of quantum mechanical molecular systems

A new approach to synthesize algorithms for selective control of the observables in quantum mechanical systems in the presence of additional constraints during the whole period of control is proposed. Analytic results of achieving the goal of control under some additional assumptions were obtained. It was demonstrated that the error in achieving the goal of control is proportionate to the error in prescribing the initial state of system and the error in realizing the control action. Numerical results for the problem of selective control for energy of hydrogen molecules (H₂) with different isotopes are represented. The proposed algorithms are easy to design.     

Structure formation in production of yttrium-silicate materials by the sol-gel method

Materials made from yttrium silicates were synthesized by the sol-gel method. The effect of the amount of yttrium oxide, which varied from 10 to 50% (molar content), and the water:alcoholate molar ratio was investigated. Structure formation and the character of crystallization of gels in heat treatment in the 650–1300°C range were investigated. __________ Translated from Steklo i Keramika, No. 1, pp. 3–6, January, 2007.     

基于目标检测的地铁站人群数量估计

为实时估计并控制地铁站的人群数量,提出了一种基于改进YOLOv3的人群数量估计方法.首先,对收集的多场景的地铁监控视频进行抽帧、采样、标注等前期处理;其次,通过上采样改进模型的输出尺度,同时以"人头"代替"人"作为检测目标训练检测模型;最后,对测试结果进行评估,验证所提出方法的有效性及实时性.实验结果表明,在地铁监控视频检测任务中,改进YOLOv3检测方法的平均准确率可以达到90.42％,每帧的检测时间大约50 ms,在达到准确率要求的同时,可以满足特定场景所需的实时检测的需求.     

Electrochemical properties and solubility of URh<Subscript>3</Subscript> in nitric acid solutions

Electrochemical properties of the intermetallic compound URh₃ in 0.5–8 M HNO₃ solutions were studied by linear voltammetry. The electrochemical characteristics of URh₃ in nitric acid solution were determined for the first time using the Tafel equation. URh₃ is highly resistant to both chemical and anodic dissolution, which is due to formation of passive films on the electrode surface. All the anodic oxidation processes observed on the electrode led to secondary passivation of the alloy and not to its dissolution. The conclusions based on the electrochemical data were confirmed by experiments in 8 M HNO₃.     

Problem of reconstructing input signals under communication constraints

For a linear controllable system, the problem of reconstruction of all input signals, which are compatible with the measured signal, is considered. It is assumed that information can be transmitted in a processing center only via digital communication channel at discrete time instants, and the word length is limited. In this connection, there are encoding and decoding devices in the communication channel. For simplicity, the communication channel is assumed to be noiseless and delay-free. Defining relationships are obtained for the set of compatible input signals, as well as relationships between reconstruction precision, length of transmitted word and transmission frequency.     

Automated layout design of beam-slab floors using a genetic algorithm

The beam-slab layout design task is an ill-defined problem. As a result, it is difficult to delegate this task to computers. This study proposes a new genetic algorithm to be used to perform this design task. First, a new coding scheme for beam-slab layouts is developed. After that, the beam-slab layout design problem is written as an optimization problem by establishing proper objective and constraint functions. To show the validity of the proposed algorithm, it is used to design beam-slab layouts of several floor plans. The obtained results show that the proposed technique is able to find good beam-slab layouts.