A new Li-ion battery charger with charge mode selection based on 0.18 um CMOS for phone applications

A new architecture of Li-Ion battery charger with charge mode selection is presented in this work. To ensure high efficiency, good accuracy and complete protection mode, we propose an architecture based on variable current source, temperature detector and power control. To avoid the risk of damage, the Li- Ion batteries charging process must change between three modes of current (trickle current (TC), constant current (CC), and constant voltage (CV)) in order to charge the battery with degrading current. However, the interest of this study is to develop a fast battery charger with high accuracy that is able to switch between charging modes without reducing its power efficiency, and to guarantee a complete protection mode. The proposed charger circuit is designed to control the charging process in three modes using the charging mode selection. The obtained results show that the Li-ion batteries can be successfully charged in a short time without reducing their efficiency. The proposed charger is implemented in 180 nm CMOS technology with a maximum charging current equal to 1 A and a maximum battery voltage equal to 4.22 V, (with input range 2.7-4.5 V). The chip area is 1.5 mm2 and the power efficiency is 90.09 %.

Study on Numerical Simulation of Geometric Elements of Blasting Funnel Based on PFC5.0

Based on the particle flow code (PFC2D) within the discrete element method (DEM), the rock mass model was established according to the site rock conditions and the rock mass blasting was simulated by the explosive particle expansion method. The influence of various parameters (the peak pressure action coefficient of the borehole wall, explosive particle buried depth, and charge mode) in the explosive particle expansion method on blasting effect was investigated. Furthermore, the relationship between the various parameters and the geometry size of the blasting crater was obtained. By comparing the size of blasting crater in the field blasting test and numerical simulation example, the reliability of rock mass blasting simulated by the explosive particle expansion method using PFC is verified. The result shows that this paper provides a reliable new numerical simulation method for rock mass blasting and can be used to guide field blasting.

Nanostructured materials based on the bronze titanium dioxide for lithium batteries in large-sized engineering

В последние годы, стремительными темпами развивается целый ряд направлений промышленности, таких как гибридный и электрический автотранспорт, подводная робототехника, сфера бесперебойного энергообеспечения, прибрежная возобновляемая энергетика, и т.п., требующих от автономных накопителей энергии работы в жёстких условиях эксплуатации. Это диктует необходимость решения ряда задач, связанных с получением для них функциональных материалов с достаточно высокими удельными характеристиками, способностью стабильно и безопасно функционировать в широком температурном диапазоне и в условиях ускоренного заряда. В этой связи все больше внимания исследователями уделяется диоксиду титана. В рамках настоящего исследования получены наноленты диоксида титана со структурой бронз гидротермальным способом с использованием анатаза, состоящего из частиц различного размера. Обнаружено, что степень кристалличности и текстурные характеристики формирующегося TiO2-B определяются размером частиц и площадью поверхности стартового реагента. В свою очередь оба эти фактора оказывают значительное влияние на электрохимические характеристики бронзовой модификации TiO2: после 35 циклов заряда/разряда емкость составила 203 мА∙ч/г, а скорость деградации – 0,25% за цикл для материала, синтезированного из анатаза с размером частиц ~30 нм и площадью поверхности ~100 м2/г. В то же время образцы, полученные с использованием более крупных частиц, показывают худшие показатели емкости и циклируемости. Now, technology progress provides broad prerequisites for practical usage of batteries in the field of hybrid and electric vehicles, marine robotics, backup uninterruptible power supplies, coastal renewable energy sources, etc. with a more hard-working performance. This dictates the necessity of development an advanced electrode materials with a sufficiently high specific parameters, stability of operation and safely in a wide temperature range and under fast charge mode. In this way, a more attention has been paid to titanium dioxide. Herein, the titanium dioxide nanobelts with a bronze structure were obtained by the hydrothermal method using anatase with different particle size as a precursor. It was found that the degree of crystallinity and textural characteristics of as-formed TiO2-B are determined by the particle size and surface area of starting reagent. Both of these factors have a benefit effect on the electrochemical performance of TiO2-B: the capacity of 203 mA·h/g was registered after 35 charge/discharge cycles with a degradation of 0.25% per cycle for material synthesized from anatase with a particle size about ~30 nm (~100 m2/g). On the other hand, the samples prepared from a precursors with larger particles show the worst capacity and cyclability.

On the topological immunity of corner states in two-dimensional crystalline insulators

A higher-order topological insulator (HOTI) in two dimensions is an insulator without metallic edge states but with robust zero-dimensional topological boundary modes localized at its corners. Yet, these corner modes do not carry a clear signature of their topology as they lack the anomalous nature of helical or chiral boundary states. Here, we demonstrate using immunity tests that the corner modes found in the breathing kagome lattice represent a prime example of a mistaken identity. Contrary to previous theoretical and experimental claims, we show that these corner modes are inherently fragile: the kagome lattice does not realize a higher-order topological insulator. We support this finding by introducing a criterion based on a corner charge-mode correspondence for the presence of topological midgap corner modes in n-fold rotational symmetric chiral insulators that explicitly precludes the existence of a HOTI protected by a threefold rotational symmetry.

Structural and Mechanical Design of Solar Tracking System

This project deals with the PV Panel arrangement and its moving technique, auto tracking elements and its design. Domestic and commercial sectors are using battery backup system to challenge the power cut. Power demand is drastically increasing unproportionally to the supply. Hence, tapping of electricity from sun is mandatory requirement. A set of PV modules are integrated to the battery backup system. The charge mode selector will assign priority to use solar energy for battery charging / usage. In this system, the sunny days are used to tap out the energy. The efficiency of the PV cells are small only but by using auto tracking system the maximum possible energy can be tapped. Worm gear configurations in which the gear can not drive the worm are said to be self-locking.In this tracking arrangement,the worm gear riveted with PV array tracks the solar radiation.

Analysis of the Hydrogen Induced Cracking by Means of the Small Punch Test: Effect of the Specimen Geometry and the Hydrogen Pre-Charge Mode

This paper presents a simplified procedure to analyse the Hydrogen Induced Cracking (HIC) of structural steels by means of the Small Punch Test (SPT). Two types of notched specimens were used: one with through-thickness lateral notch and another with surface longitudinal notch. The results for conventional specimens were compared with those for hydrogen pre-charged specimens. For this purpose, two different methods to introduce hydrogen in the specimens were used: cathodic/electrochemical pre-charging and pressurized gaseous hydrogen pre-charging. The results obtained with both methods are also discussed.