A measure for the chirality of triangles

A measure for the description of the chirality of triangles is introduced. The measure $X\delta$ is zero for triangles with at least one mirror axe, i.e. equilateral or isosceles triangles, and positive or negative for scalane, i.e. left or right handed triangles, respectively

HYDRODYNAMIC PERFORMANCE OF NEIL PRYDE RS: X AND MISTRAL SAILBOARD

After Olympic Games in 2004, the once used board, MISTRAL (M), in Olympic Game has been substituted with NEIL PRYDE RS：X (NP). To meet the need of the national sailing team, the research group carried out the experiments on the hydrodynamic performance of the NP and M early or later. The resistances, transverse forces and wrest moments were measured by using the balance of the trisection force, the angle of the heel and pitch was measured by using the angle sensor. The sailboard could rise and sink freely, the pitch was free, the static angle could be adjusted by utilizing the weight and the balance was at the mast. The results showed that the resistance of NP sailboard was bigger as soon as the pitch angle was bigger and this was the same as that of M sailboard, the heel did not have any influence on the resistance of NP sailboard, the resistance became small continuously when the angle of the centerboard decreased and the resistance increased as the sailboard was heavier

HYDRODYNAMIC ANALYSIS OF ROWING HULL BASED ON THE FLOAT POSE

The rowing is one of the important events in the Olympic Games. In order to study the hydrodynamic performance of rowing, we finished the linetype mapping and the calculated the parameters of the double rowing model. Based on the resistance data of rowing at different states, we obtained the rule of resistance of rowing at different speeds. The study indicated that the enhancement of the physical force of the athletes seemed to be in proportion to the weight of the athletes and the results based on research shallow affected and optimized the design

An integrated 80V 45W class-D power amplifier with optimal-efficiency-tracking switching frequency regulation

Piezoelectric actuators are widely used in smart materials for vibration and noise control, precision actuators, etc. [1]. These actuators are largely capacitive and the reactive power applied on them can go to several tens of Watts. Highvoltage, high-power class-D amplifiers [2]-[5] are ideal drivers for such loads, because of their high power efficiency. Preferably, efficiency should be high both at maximum power and at average output power. Obtaining high power efficiency over the full output power range of a class-D amplifier is the main focus of this work

A High-Voltage class-D power amplifier with switching frequency regulation for improved high-efficiency output power range

This paper describes the power dissipation analysis and the design of an efficiency-improved high-voltage class-D power amplifier. The amplifier adaptively regulates its switching frequency for optimal power efficiency across the full output power range. This is based on detecting the switching output node voltage level at the turn-on transition of the power switches. Implemented in a 0.14 μm SOI BCD process, the amplifier achieves 93% efficiency at 45 W output power, > 80% power efficiency down to 4.5 W output power and > 49% efficiency down to 0.45 W output power

Design and analysis of a high-efficiencyv high-voltage class-D power output stage

The analysis and design of a highly-efficient 80 V class-D power stage design in a 0.14 μm SOI-based BCD process is described. It features immunity to the on-chip supply bounce, realized by internally regulated floating supplies, variable driving strength for the gate driver, and an efficient 2-step level shifter design. Fast switching transition and low switching loss are achieved with 94% peak efficiency for the complete class-D power stage in the realized chip

HYDRODYNAMIC PERFORMANCE OF THE ROWING HULL

The viscous resistance of the rowing hull was calculated by means of 8th ITTC formula; the wave-making resistance of the rowing hull at different velocity was calculated based on the Michell integral formula. The characteristic of the total resistance of the rowing hull was discussed. The results can guide coaches and athletes to train and compete

Loss of AMIGO2 causes dramatic damage to cardiac preservation after ischemic injury

Background: Recent studies have identified amphoterin-induced gene and open reading frame (AMIGO2). The role of AMIGO2 in tumour research is well-studied, but its role in ischemic heart diseases is seldom reported. In the present study, the role of AMIGO2 in myocardial infarction (MI) is under investigation for the first time. Methods: For in vitro studies, cardiomyocytes (CMs) and endothelial cells (ECs) were isolated from both AMIGO2 knockout (KO) and WT mice. The apoptosis of CMs was tested after 48 h of ischemic stimulation. A proliferation test was implemented after 7 days of normoxic incubation and tube forma­tion on ECs. For in vivo studies, the MI model was built in mice hearts. Echocardiographic evaluation was performed at 3 days and 28 days post-MI, while the hemodynamics test was performed at 28 days post-MI. The histological results of the apoptosis, proliferation, angiogenesis and infarct zone assess­ments were determined using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assay, Ki67 staining, a-SMA/CD31 immunostain and the Masson-Trichrome method, respectively. The expression changes of the Akt pathway and related proteins were confirmed using both quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Results: The present results demonstrated that AMIGO2 deficiency caused more CMs suffering apop­tosis, lower proliferation and less angiogenesis in vitro and in vivo. Weaker cardiac function and larger scar formation were detected in AMIGO2 KO mice, and increased expression of active-caspase-3 and decreased expression of PDK1, p-Akt, Bcl-2/Bax and VEGF occurred. Conclusions: Herein the findings indicate that AMIGO2 deficiency plays an attenuated cardio-pro­tective role in ischemic heart disease via inactivation of the PDK1/Pten/Akt pathway