Total organic carbon content logging prediction based on machine learning:A brief review

The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or gas.Hence,accurately calculating the total organic carbon content in a formation is very important.Present research is focused on precisely calculating the total organic carbon content based on machine learning.At present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon content.However,the principles and perspectives of various machine learning algorithms are quite different.This paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation problems.Of various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better results.Additionally,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content prediction.The prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research block.According to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine learning.Deep learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon content.Evaluating the total organic carbon content based on machine learning is of great significance.

Tanshinone IIa antagonizes spinal ischemia/reperfusion injury by interfering with upstream glutamic acid factors

Based on the hypothesis that upstream factor inhibition results in better treatment effects than downstream factor inhibition,the present study interfered with glutamic acid（Glu）-released upstream factors,such as Glu transporter function and Na＋-K＋-adenosine triphosphatases（ATPase）activity relativly.Rats with spinal cord ischemia/reperfusion injury received intraperitoneal injections of tanshinone Ila and Glu uptake and Na＋-K＋-ATPase activity were increased.Results showed that tanshinone Ila influenced Glu-released upstream factors following spinal ischemia/reperfusion injury and protected against spinal ischemia/reperfusion injury.

Clinical Application of X-ray,B-scan,and CT in the Diagnosis of Ocular Foreign Bodies

Purpose:To analyze the sensitivity and specificity of X-ray, B-ultrasound, and CT scan in diagnosing ocular foreign bodies, and to compare the accuracy of these three imaging tools in locating these foreign bodies. Methods:A retrospective review was conducted of radio graphic and clinical eye examination data from 62 patients (66 eyes),suspected of having ocular foreign bodies at time of first presentation to the Zhongshan Ophthalmic Center (Guangzhou, China) between August 2007 and October 2011. The sensitivity and specificity of X-ray, B-ultrasound and CT scan in the diagnosis of ocular foreign bodies were investigated and their accuracy in locating these foreign bodies was compared. Results: A total of 75.8% (n=47) subjects had ocular foreign bodies; 66% of these were metallic. Patients with intraocular, eye wall,and extraocular foreign bodies accounted for 46, 28, and 26% of the total, respectively. The sensitivities of X-ray,CT scan,and B-ultrasound in the diagnosis of ocular foreign bodies were 58.3%, 61.7%, and 75%, the specificityies were 63.3%, 100%, and 87.5%, and the accuracy in locating foreign bodies was 73.4%, 94.7%, and 86.5%, respectively. The properties of foreign bodies affected the diagnosistic accuracy of X-ray,but exerted little impact upon B-ultrasound and CT scan. Conclusion:A fairly high incidence of ocular foreign bodies was noted in patients suspected with ocular foreign bodies at their first presentations.X-ray combined with CT scan or X-ray in combination with B-ultrasound showed a relatively high sensitivity and specificity in diagnosing ocular foreign bodies. CT scan had the highest accuracy in locating ocular foreignbodies. (Eye Science 2013; 28:11-14)

Retrieval of the effective constitutive parameters from metamaterial absorbers

The equivalent medium theory of metamaterials provides a way to obtain their effective constitutive parameters.However,because of its non-reciprocity,the complexity of the electromagnetic coupling,and a metallic bottom layer,it has been challenging to retrieve them from a metamaterial absorber.In this paper,we propose a method without any approximation to obtain them,in which the non-reciprocity and the strong electromagnetic coupling are included.Compared with the three methods such as symmetric metamaterial method,asymmetric metamaterial method and metasurface method,our method can reveal the metamaterial absorber’s electrical and magnetic resonance and show its electromagnetic coupling coefficients.To deal with a metamaterial absorber with a metallic bottom layer,four corners of the metallic bottom layer in the unit cell are removed,making it possible to retrieve the electromagnetic parameters.Surprisingly,these results show that the metamaterial absorber with a metallic bottom layer in our example operates in a negative refraction state at the half absorption frequencies,which helps further understand the absorbing mechanism of these metamaterial absorbers.

Revealing the interaction mechanism of pulsed laser processing with the application of acoustic emission

The mechanisms of interaction between pulsed laser and materials are complex and indistinct,severely infuencing the stability and quality of laser processing.This paper proposes an intelligent method based on the acoustic emission(AE)technique to monitor laser processing and explore the interaction mechanisms.The validation experiment is designed to perform nanosecond laser dotting on foat glass.Processing parameters are set diferently to generate various outcomes:ablated pits and irregular-shaped cracks.In the signal processing stage,we divide the AE signals into two bands,main and tail bands,according to the laser processing duration,to study the laser ablation and crack behavior,respectively.Characteristic parameters extracted by a method that combines framework and frame energy calculation of AE signals can efectively reveal the mechanisms of pulsed laser processing.The main band features evaluate the degree of laser ablation from the time and intensity scales,and the tail band characteristics demonstrate that the cracks occur after laser dotting.In addition,from the analysis of the parameters of the tail band very large cracks can be efciently distinguished.The intelligent AE monitoring method was successfully applied in exploring the interaction mechanism of nanosecond laser dotting foat glass and can be used in other pulsed laser processing felds.

Rectangular dielectric metagrating for high-efficiency diffraction with large-angle deflection

In this Letter,we propose a metagrating consisting of simple rectangular bars for nearly unity anomalous diffraction with a large deflection angle.The analysis performed by the scattering-matrix method shows that such exceptional beam steering derives from the couplings of the two lowest propagation waveguide-array-modes and their constructive interferences.The tolerance of the incident angle for a high diffraction efficiency(e.g.,>90%)is within a range of 33°.We also discuss that such an advantage still exists after considering a reasonable loss and dispersion.We envision that the proposed strategy may have wide use in the field of high-performance wavefront-shaping applications.