Simulation Study on Material Property of Cantilever Piezoelectric Vibration Generator

Abstract: For increasing generating capacity of cantilever piezoelectric vibration generator with limited volume, relation between output voltage, inherent frequency and material parameter of unimorph, bimorph in series type and bimorph in parallel type piezoelectric vibration generator is analyzed respectively by mechanical model and finite element modeling. The results indicate PZT-4, PZT-5A and PZT-5H piezoelectric materials and stainless steel, nickel alloy substrate material should be firstly chosen. Copyright © 2014 IFSA Publishing, S. L

7-(6-Bromo­hex­yloxy)-4-methyl-2H-chromen-2-one

In the title mol­ecule, C16H19BrO3, all non-H atoms apart from the Br atom are approximately coplanar, with a maximum deviation of 0.242 (4) Å. The C—C—C—Br torsion angle is 66.5 (4)°

1,5-Bis(4-bromo­phen­yl)-3-phenyl­pentane-1,5-dione

The asymmetric unit of the title compound, C23H18Br2O2, contains two independent mol­ecules with slightly different conformations. In the absence of classical inter­molecular inter­actions, the crystal packing is stabilized by van der Waals forces

Analyzing the formation of normal and abnormal O waves in thoracic impedance graph using the impedance change components for aorta, blood vessels in lung and ventricles

Background: Many measurements of thoracic impedance graph show that the small C wave and big O wave appear often for patients with cardiac insufficiency, and the O/C ratio is bigger. And for the normal body, especially a younger one, the bigger O wave may also appear. But since the amplitude of the C wave of a normal body is bigger, the O/C ratio is smaller. The aim of the present paper is to investigate the formation mechanism of the normal and abnormal O waves in thoracic impedance graph. Methods and Results: The thoracic mixed impedance changes are measured with 6 leads consisting of 15 electrodes. The impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV) and right ventricle (RV) are separated from thoracic mixed impedance changes by means of establishing and solving the thoracic impedance equations. The amplitudes of the O and C waves of various impedance change components are measured for 50 normal healthy adults and 34 patients with cardiac insufficiency. The formation mechanism of normal and abnormal O waves in thoracic impedance graph is analyzed using the superposition of the O waves of the above impedance change components. Detection subjects are 50 healthy adults and 34 hospital patients with cardiac insufficiency. (1) Thoracic impedance graph: The O/C ratios of the normal group are significantly smaller than that of the abnormal group, p < 0.001. The O wave of first lead (E1-E1’) is significantly bigger than that of leads 4 and 5 (E4-E4’ and E5-E5’) in the normal group, p < 0.001. (2) The impedance change component: The O waves of the AO, PL, and PR are significantly smaller than that of the LV and RV in the normal group, p < 0.001. The O wave and O/C of the AO, PL and PR of normal group are significantly smaller than that of the abnormal group, p < 0.001. Conclusions: The O wave of the thoracic impedance graph is formed due to the superposition of the O waves of the impedance change components for the aorta, blood vessels in lung and ventricles

Modeling and Simulation of Piezoelectric Vibration Generator for Powering Wireless Sensor Networks

Micro piezoelectric vibration generator with high energy density may provide infinite and continuous energy for wireless sensor network. In order to improve generating capacity under given dimension, aiming at external force and displacement incentive environment, mathematics model of piezoelectric cantilever generator generating capacity are established, and influence law of unimorph and bimorph piezoelectric generator structural parameter on output voltage are analyzed by finite element simulation. The results show that on external force incentive environment, the output voltage increase linearly while length increase and decrease inverse proportion while width increase; on displacement incentive environment, the output voltage decrease while length increase and don't change while width vary; meanwhile, relation between thickness ratio and output voltage isn't affected by incentive environment, and bimorph piezoelectric generator with low thickness ratio should be selected at first for obtaining higher output voltage

9-(4-Bromo­but­yl)-9H-carbazole

In the title compound, C16H16BrN, the bromo­butyl group lies on one side of the carbazole ring plane and has a zigzag shape. The dihedral angle between the two benzene rings is 0.55°. In the crystal, mol­ecules are connected by van der Waals inter­actions