Reliability testing and reliability analysis of the over-load protective relay

The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products.

Carvedilol suppresses ventricular arrhythmia in a pressure over-load rabbit model through relieving transmural dispersion of repolarization with long-term administration

Objective： To investigate the effects of carvedilol （CVD） on transmural dispersion of repolarization（TDR） and arrhythmia in pressure over-load rabbits. Methods： Left ventricular hypertrophied（LVH） rabbit models were established by pressure over-load; All animal models were assigned into CVD group or LVH group randomly. The action potentials of endocardium, cpicardium and transmural ECG of arterially perfused left ventricular preparations were recorded concurrently. Action potential duration （APD）, TDR, ventricular arrhythmia and ultrasonic parameters, ratio of LVM to body weight （LVMI） were compared correspondingly. The stable plasma concentration of carvedilol in CVD group was detected by HPLC. APD, TDR and arrhythmia of LVH models were compared just preor post-perfusion with stable concentration of CVD. Results： In Contrast with values in LVH group, LVEFof CVD group were significantly elevated while the LVMI was remarkably reduced, TDRs were significantly shortened, and ratio of ventricular arrhythmia was lowered remarkably. No significant difference of APD, TDR and ratio of arrhythmia was found preor post-perfusion at stable plasma concentration of CVD. Conclusion： CVD can ameliorate the structure and function of pressure over-load ventricles; CVD contributes to the improvement of ventricular arrhythmia associated with its long-term effect on APD,TDR shortening ,whereas has nothing to do with its transient function on ionic channel blockade

STUDY ON POWER SPARE COEFFICIENT OF ELECTRICAL MOTOR IN LARGE PUMP STATION BASED ON RELIABILITY

Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.

A survey of research in brain iron level and Alzheimer’s disease

The main pathological feature of Alz-heimer’s disease(AD)is the extracellular deposition ofβ-amyloid(Aβ)in the brain,which forms insoluble Aβplaques,and tau protein hyperphosphorylation in neu-rons,which forms intracellular fibrillary tangles.So far,none of the drugs targeting Aβhave been successful in the treatment of AD.Some studies have shown that brain iron deposition may be one of the important factors in AD pathogenesis;the distribution of iron deposition has been found to be consistent with the distribution of Aβsenile plaques in the brain.Effectively reducing brain iron load might therefore be a good therapeutic approach to prevent and treat AD.

Protective role of a novel human erythrocyte-derived depressing factor on blood vessels in rats

The protective role of a human erythro-cyte-derived depressing factor (EDDF) on blood vessels was evaluated. The experiments were carried out on 25 male Wistar rats aged 6-8 weeks, which were divided into control (n=8), calcium overload (n=8) and NG-L-nitro-arginine hypertensive model groups (L-NNA, n = 9), respectively. The isolated vascular ring perfusion assay, two-photon laser scanning fluorescence microscopy (TPM) and transmitted electron microscope were used to examine the effect of EDDF on vascular function and ultrastructure. Results showed that the contractile response of calcium overload rats and L-NNA rats to phenylephrine (PE) was significantly enhanced compared with that of the control (P 【 0.05), and EDDF (10-3g·mL-1) remarkably decreased the vascular contractile response of control’s and calcium overload rats (P 【 0.05), while EDDF had no effect on that of L-NNA rats. EDDF also alleviated the ultrastructural lesion of aorta VSMC in calcium overload rats by easing the abnormal in the