测井新技术在四川油气勘探开发中的应用

综述随着四川盆地油气勘探深入所面临的油气领域复杂和困难的技术问题，介绍应用测井新技术为四川油气开发解决了大量的技术难题，特别是在复杂缝，洞型储层的评价，井旁地质构造形态精细分析和地质，测井，地震多学科结合储层横向预测等3个方面所取得的良好应用效果。     

Channel-carrier mobility parameters for 4H SiC MOSFETs

In this paper, mobility parameters for enhancement-mode N-channel 4H SiC MOSFETs are extracted and implemented into 2-D device simulation program and SPICE circuit simulator. The experimental data were obtained from lateral N-channel 4H SiC MOSFETs with nitrided oxide–semiconductor interfaces, exhibiting normal mobility behavior. The presence of increasing interface-trap density (D_it) toward the edge of the conduction band is included during the 2-D device simulation. Using measured distribution of interface-trap density for simulation of the transfer characteristics leads to a good agreement with the experimental transfer characteristic.     

Exploiting probability density function of deep convolutional autoencoders’ latent space for reliable COVID-19 detection on CT scans

The Journal of Supercomputing - We present a probabilistic method for classifying chest computed tomography (CT) scans into COVID-19 and non-COVID-19. To this end, we design and train, in an...     

The synthesis of nano-sized ZSM-5 zeolite by dry gel conversion method and investigating the effects of experimental parameters by Taguchi experimental design

In this study ZSM-5 Nano particles with high crystallinity were synthesized using a dry gel conversion technique. An L9 orthogonal array of the Taguchi method was applied to investigate the effect of synthesis parameters, such as crystallization time, gel drying temperature, molar composition of template (TPAOH) and water content in the crystallization stage on crystallinity and particle size of the ZSM-5 catalyst. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Beside short crystallization time, the particle sizes were considerably smaller in comparison with those prepared using the hydrothermal method. The results showed that the particle size and crystallinity increased with increasing water content and crystallization time. The effects of gel drying temperature and molar composition of template were found to be more complex, however. Comparing to hydrothermal method, ZSM-5 samples synthesized with the dry gel conversion exhibited higher selectivity to gasoline than other hydrocarbons.     

Serum from diabetic BB/W rats enhances calcium currents in primary sensory neurons

We examined the hypothesis that exposure of nondiabetic rat dorsal root ganglion (DRG) neurons to sera from diabetic BB/W rats would produce an increase in calcium currents associated with impaired regulation of the inhibitory G protein-calcium channel complex. Acutely dissociated rat DRGs were incubated for 18-24 h in medium supplemented with sera (10% vol/vol) from either diabetic rats with neuropathy or age-matched, nondiabetic controls. Exposure of DRG neurons to sera from diabetic BB/W rats resulted in a surface membrane immunofluorescence pattern when treated with an anti-rat light-chain antibody that was not observed in neurons exposed to control sera. Calcium current density (IDCa) was assessed with the use of the whole cell variation of the patch-clamp technique. IDCa in neurons exposed to diabetic sera was significantly increased compared with neurons exposed to control sera. Guanine nucleotide-binding (G) protein regulation of calcium channel function was examined with the use of a two-pulse "facilitation" or IDCa enhancement protocol in the presence of activators [guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S)] or antagonists [guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) and pertussis toxin (PTX)] of G protein function. Facilitation was significantly decreased in neurons exposed to diabetic sera. Intracellular diffusion of neurons with GDP beta s blocked facilitation, whereas dialysis with GTP gamma s increased facilitation to a similar magnitude in neurons exposed to either diabetic or control sera. Treatment with PTX resulted in a significant increase in IDCa and approximately 50% decrease in facilitation in neurons treated with control sera but no significant changes in neurons exposed to diabetic sera. We conclude that serum from diabetic BB/W rats with neuropathy contains an autoimmune immunoglobulin that impairs regulation of the inhibitory G protein-calcium channel complex, resulting in enhanced calcium influx. Regulation of the inhibitory G protein-calcium channel complex involves PTX-sensitive and -insensitive G proteins.     

Inter-image outliers and their application to image classification

Image variability that is impossible or difficult to restore by intra-image processing, such as the variability caused by occlusions, significantly reduces the performance of image-recognition methods. To address this issue, we propose that the pixels associated with large distances obtained by inter-image pixel-by-pixels comparisons should be considered as inter-image outliers and should be removed from the similarity calculation used for the image classification. When this method is combined with the template-matching method for image recognition, it leads to state-of-the-art recognition performance: 91% with AR database that includes occluded face images, 90% with PUT database that includes pose variations of face images and 100% with EYale B database that includes images with large illumination variation.     

Using satellite data to extract volume–area–elevation relationships for Urmia Lake,Iran

Urmia Lake in the northwest of Iran is the second largest hyper-saline lake worldwide. During the past two decades, a significant water level decline has occurred in the lake. The existing estimations for the lake water balance are widely variable because the lake bathymetry is unknown. The main focus of this study is to extract the volume–area–elevation (V–A–L) characteristics of Urmia Lake utilizing remote sensing data and analytical models. V–A–L equations of the lake were determined using radar altimetry data and their concurrent satellite-derived surface data. Next, two approximate models, a power model (PM) and a truncated pyramid model (TPM), were parameterized for Urmia Lake and checked for accuracy. Results revealed that in comparison with the satellite-derived reference volume–elevation equation, the PM slightly over-predicts the volume of Urmia Lake while the TPM under-estimates the lake storage. Variations of the lake area and volume between 1965 and 2011 were examined using the developed V–A–L equations. Results indicated that the lake area and volume have declined from the historical maximum values by 2200 km² and 33 km³, respectively. To restore Urmia Lake to a level to maintain ecological benefits, 13.2 km³ of water is required. This study demonstrates the use of remote sensing data of different types to derive V–A–L equations of lakes. Substituting satellite-derived V–A–L equations for common empirical formulas leads to more accurate estimations of a lake water balance, which in turn, provides insight to water managers for properly assessing and allocating water resources to downstream ecosystems.     

A two-dimensional warranty servicing strategy based on reduction in product failure intensity

The cost of servicing a warranty depends, amongst other factors, on the type of repair performed under warranty. Although “all minimal repair” and “all replacement” policies are easy to implement and analyze, they are not always feasible and/or practical. Having a combination of different types of repair often leads to lower warranty servicing costs. In this article, to reduce the warranty servicing cost, we study a servicing strategy that involves performing imperfect repairs in place of some of the minimal repairs of an “all minimal repair” strategy; the effect of an imperfect repair is characterized by a drop in the conditional intensity function of the failure process. We consider both fixed and random degrees of repair. For a given type of product, we partition the warranty region so that the expected total warranty servicing cost is minimized. We provide a numerical illustration and a comparison with previously-studied repair-replacement strategies.