Novel Reconnection-less Reconfigurable Filter Design Based on Unknown Nodal Voltages Method and Its Fractional-Order Counterpart

A novel solution of reconnection-less electronically reconfigurable filter is introduced in the paper. The filter is designed based on unknown nodal voltages method (MUNV) using operational transconductance amplifiers (OTAs) and variable gain amplifier (VGA). The structure can provide all-pass, band-stop, high-pass 2nd order functions, high-pass function of the 1st order and direct transfer from the same topology without requirement of manual reconnection. The proposed structure also offers the electronic control of the pole frequency. Moreover, fractional-order design of the proposed filter is also provided. The behavior is verified by simulations using Cadence IC6 (spectre) software

Source for In Situ Positron Annihilation Spectroscopy of Thermal-And Hydrogen-Induced Defects Based on the Cu-64 Isotope

This work aims to investigate the 64Cu isotope applicability for positron annihilation experiments in in situ mode. We determined appropriate characteristics of this isotope for defect studies and implemented them under aggressive conditions (i.e., elevated temperature, hydrogen environment) in situ to determine the sensitivity of this approach to thermal vacancies and hydrogen-induced defects investigation. Titanium samples were used as test materials. The source was obtained by the activation of copper foil in the thermal neutron flux of a research nuclear reactor. Main spectrometric characteristics (e.g., the total number of counts, fraction of good signals, peak-to-noise ratio) of this source, as well as line-shaped parameters of the Doppler broadening spectrum (DBS), were studied experimentally. These characteristics for 64Cu (in contrast to positron sources with longer half-life) were shown to vary strongly with time, owing to the rapidly changing activity. These changes are predictable and should be considered in the analysis of experimental data to reveal information about the defect structure. The investigation of samples with a controlled density of defects revealed the suitability of 64Cu positron source with an activity of 2-40 MBq for defects studies by DBS. However, greater isotope activity could also be applied. The results of testing this source at high temperatures and in hydrogen atmosphere showed its suitability to thermal vacancies and hydrogen-induced defects studies in situ. The greatest changes in the defect structure of titanium alloy during high-temperature hydrogen saturation occurred at the cooling stage, when the formation of hydrides began, and were associated with an increase in the dislocation density

Recrystallization of CaCO3 submicron magnetic particles in biological media

Background and Objectives: The development of magnetic theranostics is associated with the determination of the behavior of magnetic carriers in biosimilar media. In this work, we analyze the formation of different crystalline phases from magnetic mineral submicron calcium carbonate particles during incubation under conditions of cell cultivation in vitro for 3 days. The study of mineralmagneticsubmicron particles recrystallization was analyzed by XRD and electron scanning microscopy. The shape of calcium carbonate particles begins to change from elliptical to spherical under cell culture cultivations. As the amount of magnetite nanoparticle particles in calcium carbonate increases, the recrystallization process is faster with fallout of calcite, vaterite and magnetite phases. Materials and Methods: Scanning electron microscopy, processing of results using a self-written Python code, XRDwere utilized in this study. Results: The study of the process of recrystallization of magnetic mineral particles shows has shown that increasing the content of magnetic carriers leads to accelerated recrystallization of particles with simultaneous precipitation of calcite, vaterite and magnetite phases. Conclusion: Magnetic mineral submicron calcium carbonate particles are promising targets for theranostics with the self-destruction property in biological environments

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Research of Energy Saving Mode of Building Distributed Control System Under Influence of Many Disturbing Factors

A model of the building heating system, consisting of energy source, a distributed automatic control system, elements of individual heating unit and heating system is designed. Application Simulink of mathematical package Matlab is selected as a platform for the model. There are the specialized application Simscape libraries in aggregate with a wide range of Matlab mathematical tools allow to apply the “acausal” modeling concept. Implementation the “physical” representation of the object model gave improving the accuracy of the models. Advanced weather block allowed to investigate the efficiency of the control system with dynamically changing the numerous factors affecting the building energy consumption for maintaining optimal climate parameters. The conducted research of heating system and automatic control system allowed estimate efficiency of control system regulating process. The results of research of thermal condition premises, situated in the different sides of the building facade are given. The conclusions about the possibility of increasing the operational efficiency of heating system in the implementation of distributed control systems are presented

Розрахунок електротеплових процесів імпульсних перетворювачів з метою забезпечення теплового захисту

Power electronics and their thermal protection systems that are designed on the basis of modern methods of thermal calculations work efficiently under specified operating conditions in a particular operating range of temperatures and modes beyond which the form of the transition process can change. Consequently, the extent of oscillation in the transition process increases along with the initial voltage and current fluctuations. These changes are dangerous if the boundary values of the component parameters are underestimated due to heating.The study suggests a method of integrated electrothermal calculation in order to ensure thermal protection of pulse converters for electric power by creating combined models of the circuit elements in the form of a system of differential equations. Analysis of the characteristic roots of solutions of the differential equations of the system state in the form of matrix exponentials gives an idea about the nature of the transition process. This allows setting a threshold value of fluctuations and a time frame of the transition process while enabling a heated device. It becomes possible to stabilize the transition process by heating the components and to choose magnetic materials of inductors, taking into account the thermal processes.As a result of this approach, thermal protection of power transformers extends to providing trouble­free operation at non­stationary modes of the components and extreme temperatures; it becomes possible to reduce the complexity and rigidity of the requirements to establishing a time frame for restarting the device.С помощью дифференциальных уравнений состояния системы описаны расчёты переходных и установившихся режимов работы импульсных преобразователей. Данные расчеты в матричной форме разделяются на электромагнитную и тепловую составляющие. Решения данных дифференциальных уравнений анализируются с точки зрения установления тепловой защиты преобразователя без добавления устройств тепловой защиты. Получено решение электротепловых уравнений системы, с помощью которого можно подбором материалов пассивных элементов и выбором активных элементов с определенными граничными значениями избежать тепловых аварий преобразователя.За допомогою диференційних рівнянь стану системи описані розрахунки перехідних і установлених режимів роботи імпульсних перетворювачів. Дані розрахунки в матричній формі розділяються на електромагнітну і теплову складові. Рішення даних диференційних рівнянь аналізуються з точки зору забезпечення теплового захисту перетворювача без додавання пристроїв теплового захисту. Отримано рішення електротеплових рівнянь системи, за допомогою якого можна підбором матеріалів пасивних компонентів та вибору активних компонентів з певними граничними значеннями уникнути теплових аварій перетворювача.

Role of External Fibrillation in High-consistency Pulp Refining

The mechanical and hydrodynamic phenomena occurring in the refining zones of disc refiners cause fibres to undergo fibrillation. This paper presents a study of the changes occurring during fibre fibrillation as expressed in terms of the fibrillation index when refining pulp with a 10%, 15%, and 20% consistency. The influences of the tangential force of a circular bar and a straight bar on fibre fibrillation were compared. The changes in the tangential force are shown to depend on the angle between the tangent to the cutting edge and the radius from the centre of the disk to the tangency point. Increasing the angle between the tangent to the cutting edge and the radius from the centre of the disk to the tangency point gives higher fibrillation index values. The study revealed a relationship between fibre fibrillation and the strength characteristics of handsheets

Prospects for the development and use of a clay-nitrogen mixture as a fertilizer

The purpose of this work is to obtain and evaluate the fertilizing ability of the clay-nitrogen mixture. The relevance of the research lies in studying issues related to the minimization of nitrogen losses when producing the clay-nitrogen fertilizer, the transformation of nitrogen from fertilizer into the soil, and the effectiveness of fertilization when growing barley. The data on the content of nitrate nitrogen (250,986 mg/kg) and the total one (5.0%) indicate the effective binding of nitric acid by clay. The fertilizer can be considered potassium-containing, since the content of mobile and total potassium is respectively 1,250 mg/kg and 0.20%. Mobile phosphorus in the fertilizer is low compared to potassium (76 mg/kg), although the total pool is twice as large (0.45%). The content of the gross form of copper (8.9 mg/kg) and zinc (9.5 mg/kg) corresponded to the MPC

The Decellularized Cell-Derived Extracellular Matrix Enhances the Paracrine Function of Human Mesenchymal Stromal/Stem Cells

The mesenchymal stromal/stem cells (MSCs) are known to secrete pleiotropic paracrine factors, contributing to tissue regeneration. This unique ability makes MSCs promising therapeutic tools for many diseases, including even those that were previously untreatable. Thus, the development of preconditioning approaches aimed at enhancing the paracrine function of MSCs attracts great interest. In the present work, we studied how the extracellular matrix, the essential part of the native tissue microenvironment, affects the secretory capacity of MSCs of various origins. The MSC-derived decellularized extracellular matrix (dECM), used as the cell culture substrate, triggered strong upregulation of FGF-2, MMP-1, HGF, GRO-α, GRO-β, CXCL-5, CXCL-6, IL-6, IL-8, G-CSF and MCP-1. Functional in vitro tests revealed that conditioned media derived from MSCs cultured on dECM significantly improved 3T3 fibroblast and HaCaT keratinocyte scratch wound healing, stimulated THP-1 monocyte migration and promoted capillary-like HUVEC-based tube formation compared to conditioned media from MSCs grown on plastic. In addition, we found that FAK inhibition promoted dECM-induced upregulation of paracrine factors, suggesting that this kinase participates in the MSCs’ paracrine response to dECM. Together, these findings demonstrate that dECM provides cues that considerably enhance the secretory function of MSCs. Thus, dECM usage as a cell culture substrate alone or in combination with a FAK inhibitor may be viewed as a novel MSC preconditioning technique