就企业应收帐款管理谈预警监控机制的建立

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INDUCTION MOTOR SPEED CONTROL SYSTEM BASED ON FUZZY NEURAL NETWORK

A fuzzy neural network controller with the teaching controller guidance and parameter regulations for vector-controlled induction motor is proposed. The design procedures of the fuzzy neural controller and the teaching controller are described. The parameters of the membership function are regulated by an on-line learning algorithm. The speed responses of the system under the condition, where the target functions are chosen as I qs and ω, are analyzed. The system responses with the variant of parameter moment of inertial J, viscous coefficients B and torque constant K tare also analyzed. Simulation results show that the control scheme and the controller have the advantages of rapid speed response and good robustness.

LOW COST IMPLEMENTATION OF SPEED SENSORLESS INDUCTION MOTOR CONTROL USING STATOR FLUX ORIENTATION

The control platform of the induction motor （IM） with low costs is developed by using DSP MC56F8013 with a good performance/price rtaio. The control algorithm for the speed sensorless IM is studied based on the stator flux orientation （SFO）. The algorithm structure is simple to be implemented and cannot be influenced by motor parameters, The improved stator flux estimation is used to compensate errors caused by the low pass filter （LPF）. A new speed regulator is designed to ensure the system working with the maximal torque in the transient state. The system simulation and the prototype experiment are made. Results show that the con- trol system has good dynamic and static performance.

A GPCR/secretase complex regulates β- and γ-secretase specificity for Aβ production and contributes to AD pathogenesis

Dysregulation of β-site APP-cleaving enzyme （BACE） and/or γ-secretase leads to anomalous production of amyloid-β peptide （Aβ） and contributes to the etiology of Alzheimer＇s disease （AD）. Since these secretases mediate proteolytic processing of numerous proteins, little success has been achieved to treat AD by secretase inhibitors because of inevitable undesired side effects. Thus, it is of importance to unravel the regulatory mechanisms of these secretases. Here, we show that δ-opioid receptor （DOR） promotes the processing of Aβ precursor protein （APP） by BACE1 and γ-secretase, but not that of Notch, N-cadherin or APLP. Further investigation reveals that DOR forms a complex with BACE1 and γ-seeretase, and activation of DOR mediates the co-endocytic sorting of the secretases/ receptor complex for APP endoproteolysis. Dysfunction of the receptor retards the endocytosis of BACE1 and γ-secretase and thus the production of Aβ Consistently, knockdown or antagonization of DOR reduces secretase activities and ameliorates Aβ pathology and Aβ-dependent behavioral deficits, but does not affect the processing of Notch, N-cadherin or APLP in AD model mice. Our study not only uncovers a molecular mechanism for the formation of a DOR/secretase complex that regulates the specificity of secretase for Aβ production but also suggests that intervention of either formation or trafficking of the GPCR/secretase complex could lead to a new strategy against AD, potentially with fewer side effects.

Debates on the Causes of Global Warming

The controversy between the IPCC and Non-governmental IPCC(NIPCC) on the attribution of global warming are reviewed.IPCC holds that today's global warming is mainly due to anthropogenic activities rather than natural variability,which is emphasized by NIPCC.The surface temperature observations since the mid-20th century support the hypothesis of anthropogenic impact,but for the last one hundred years or so,natural forcings such as solar activity, volcanic eruptions and thermohaline circulation variations also have had great influences on the Earth's climate,especially on inter-decadal timescales.In addition,evidence suggests that the Medieval Warm Period(MWP) and Little Ice Age (LIA) are closely associated with the solar activity over the past 1 thousand years.Over the past 10 thousand years, the North Atlantic cold events and solar activity are closely correlated.Nevertheless,the physical mechanisms of the solar-climate variability and interrelation are not well understood,yet.Notably,a prevailing view recently indicates that galactic cosmic rays may result in climatic cooling through modulating global low cloud cover.However,its process and mechanism need to be further investigated.

Atrial fibrosis： an obligatory component of arrhythmia mechanisms in atrial fibrillation？

Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasing anisotropy of impulse propagation and building of boundaries that promote re-entry in the atrial walls that maybe directly relevant for the mechanisms responsible for maintaining AF. Whether or not fibrosis is a result of structural remodelling caused by persistent AF or a manifestation of occult myocardial process that leads to development of arrhythmia is less clear. Human data indicate the presence of association between persistency of AF and the extent of structural changes in atrial myocardium. The role atrial fibrosis plays in the mechanisms of AF, however, may differ between patients with structurally normal hearts, such as lone AF, and those with advanced cardiovascular comorbidities.

Simulation study on the starting characteristics of a kind of improved direct torque control system

Analyzed working principle and starting process of asynchronous motor direct torque control system. In order to solve the problem of serious fluctuation of starting current in traditional control scheme, the author puts forward a new kind of starting method which can limit voltage value to achieve the goal of reducing fluctuation of the current by increasing zero voltage vectors during the stage of starting. The author has also carried on simulation study on the system, and the result of simulation study shows that this method is effectual.

Fuzzy Logic Controlled Induction Motor Based Intelligent Controller

The indirect vector controlled IM （induction motor） drive involves decoupling of the stator current into torque and flux producing components. This paper proposes the implementation of a fuzzy logic control scheme applied to a two d-q current components model of an induction motor. An intelligent based on fuzzy logic controller is developed with the help of knowledge rule base for efficient control. The performance of fuzzy logic controller is compared with that of the proportional integral controller in terms of the settling time and dynamic response to sudden load changes. The harmonic pattern of the output current is evaluated for both fixed gain proportional integral controller and the fuzzy logic based controller. The performance of the IM drive has been analyzed under steady state and transient conditions. Simulation results of both the controllers are presented for comparison.

Modern Multilevel Control Technique Used in Electric and Hybrid Drive System with Induction Motors

The mathematical model of the modem induction traction motor （TRIM and cutting magnetic circuit traction motor）, supplied with IPM inverter with different control technique is presented in the paper. In electric and hybrid vehicle are applied： FLMC （Fuzzy Logic Mode Control）, SLMC （Sliding Mode Control）, NRMC （Neural Regulator Control）, and Direct Power and Torque Control for Space Vector Modulated inverter （DPTC SVM）. In the special solution of the electric and hybrid vehicle are also applied a Random Switching Frequency Modulation. The control of hybrid vehicle should assure the realization of established transport-assignments in the definite time, at the optimum of energy consumption. One can this realize using. The multi criteria control system. Some results of the computer simulations are presented in the paper. Results of numerical calculation were verified for laboratory model of the electric and hybrid wheel vehicles traction motor.

Investigation of Interline Dynamic Voltage Restorer with Virtual Impedance Injection

The inter-line dynamic voltage restorer （IDVR） consists of several voltage source inverters connected to different independent distribution feeders with common dc bus. When one of the inverters compensates for voltage sag that appears in its feeder （voltage control mode）, the other inverters pump the required power into the dc bus （power control mode）. Each inverter will have both voltage and power controllers; only one controller is in use during the abnormal conditions according to its feeder state. The voltage controller uses one of the dynamic voltage restoration techniques. In this paper, the in-phase technique is applied and two types of loads are considered （constant impedance and three phase induction motor）. Since the voltage restoration process may need real power injection into the distribution system, the power controller injects this power via voltage injection. This voltage injection is simulated by voltage drop across series virtual impedance. A new scheme is proposed to select the impedance value. The impedance value is selected such that the power consumed by this impedance represents the required power to be transferred without perturbing the load voltage. The performance of this system is also studied during voltage swell. A scheme for operation of multi-feeder IDVR system is proposed in this paper. Simulation results substantiate the proposed concept.

Ontogenetic mechanisms underlying sexual size dimorphism in Urodele amphibians： An across-species approach

Why do two sexes of the same species differ in body size holds a long-standing question of evolutionary biology. While many across-species comparisons have focused on ultimate causes behind sexual size dimorphism （SSD）, only have a few been directed toward elucidating its ontogenetic basis. Urodeles are an amphibian group in which the direction and degree of SSD vary greatly among species. Using demographic data yielded by skeletochronology for 33 urodele species, the current study re- veals a positive across-species correlation between SSD and the sex difference in mean age of adult animals, and the latter in- creases with the corresponding difference in age at maturity; annual growth rate does not differ between the sexes. We conclude that extended longevities in one sex, which is mediated by delayed maturation, would allow it to grow for longer and get larger, with growth rate making a weak contribution to body size. The sex-specific divergence in ontogenetic trajectory might be ex- plained by potentially high growth costs of reproduction to females in association with stronger fecundity selection, and to males that are expected to experience stronger sexual selection [Current Zoology 59 （1）： 142-150, 2013].