Search

This study assesses the spatial distribution characteristics and ecological risk of phthalate esters (PAEs) in the surface sediments of the mainstream and tributaries of the Songhua River, China, using concentrations and composition of six PAEs, which were analyzed using gas chromatography-mass spectrometery (GC-MS). We assess the ∑

Laser-induced periodic surface structure (LIPSS) is a universal phenomenon which occurs for both continuous laser and pulsed laser. Recently, most studies are focus on LIPSS irradiated by fs laser. However, LIPSS irradiated by continuous laser still need to be carefully studied. Here, We study LIPSS in silicon wafer irradiated by continuous laser for different duration time and power. For the same power, we can observe the evolution process of LIPSS for different time. It is surprising that the evolution process of LIPSS seems to be layered, which occurs for different power. The inner layer occurs at first, then the outer layer occurs. Our study can be used to control the formation of LIPSS.

A new criterion to detect the stator single-phase-to-ground fault for Powerformer is proposed in this paper, which is based on the direction of leakage currents, magnitude of leakage currents, and fault point energy dissipation. New fault characteristics of Powerformer are analyzed and a novel criterion is put forward. The proposed approach detects the ground fault by analyzing the direction, magnitude, and energy of leakage current, which is the difference of zero-sequence current fault component between the neutral and the terminal of Powerformer. The fundamental component and the third-harmonic component of leakage current are combined to realize 100% coverage of fault detection for the stator windings of Powerformer. Simulation results have shown that, under different fault conditions, the new scheme can distinguish internal faults from external faults reliably, and can detect in which machine a stator single-phase-to-ground fault is occurring even if the fault resistance is at 5 kΩ.

As a new strategy to effectively use wood and plastic wastes, composites of high content wood flour (WF) and recycled high density polyethylene (RHDPE), with and without maleic anhydride polyethylene (MAPE) as compatibilizer, were prepared by direct extrusion using a twin-screw/single- screw extruder system. The effects of MAPE on the properties of composite were investigated by mechanical tests, torque rheological analysis, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results demonstrated that MAPE greatly improved the mechanical properties of the prepared WF/RHDPE composites. This was attributed to the strong improvement effects of MAPE on the interfacial interaction of the composites, as was confirmed by the torque rheological and SEM analysis. According to the DSC results, composites with 60% WF content show lower crystallinity degree (Xc) and melting temperature (Tm) than RHDPE, but the values for Tm and Xc did not have noticeable changes with the addition of MAPE.

Due to the complexity of ART network, the setting of parameters is rather difficult. Based on analyzing the architecture and the membrane equation of layer 2 (L2) in ART1 network, this paper describes the oscillation possibility of the activities of neurons in L2 layer and studies the influence of parameters setting on the behavior of L2 layer, such as the number of neurons (S/sub 2/), the biases /sup +/b and /sup -/b, the initial value of L1-L2 connection matrix W/sup 1:2/, through a simulation case whose transfer function is faster-than-linear. It also suggests a few basic principles of the parameters setting.

To explore the cause and the treatment of liver hydatidosis complicated by biliary fistula, to reduce or prevent the incidence of the complication.From 1982 to 2002, 1 666 patients with liver hydatidosis were treated surgically in our hospital, and a retrospective analysis was conducted in 13 from the cohort, who developed biliary fisltula after the surgeries.The incidence of liver hydatidosis-associated biliary fistula was 0.78% (13/1666), and 8 (61.5%) out of such cases were due to the primary liver hydatidosis, 3 (15.38%) were caused by damage to the small accessory hepatic duct or parahepatic byliary duct, and 2 (7.69%) by the puncture of the needle.Biliary fistula often arises from liver hydatidosis itself, and can be partly attributed to erroneous operation on the part of the operators, and prevention of this complication, therefore, is possible through careful operation.