Electrical resistivity is one of the fundamental physical properties of rocks, and its relationship with fluid saturation is widely used in reservoir evaluation. The interpretation of electrical logs usually relies on the results of rock resistivity tests of cores in the laboratory. In the laboratory, core samples are commonly cut into cylinders, and the resistivity is measured along the axial direction. To determine the rock resistivity along different directions, samples are cut into cubes and tested along three perpendicular directions to obtain resistivity data. The expensive and complicated preparation process of cubic samples and the custom holder requirements limit the use of these tests. We analyzed the advantages and disadvantages of rock resistivity measurements of cylindrical and cubic samples. To overcome the difficulties above, we developed a core holder for radial resistivity measurements and proposed a radial resistivity measurement method for cylindrical samples. Based on the conformal transformation of the complex variable function theory, we established a mathematical model of radial resistivity. We developed a measurement method of radial resistivity according to the mathematical model and verified this approach with isotropic cores. The theoretical calculation results agree with the experimental results. With the radial resistivity measurement method, we effectively tested the resistivity anisotropy of shale. This method has more advantages than existing methods in terms of the sample preparation and realization of various displacement levels and angles. Hence, the proposed method can be widely used.

A static VAR compensator (SVC) is a critical component for reactive power compensation in electric arc furnaces (EAFs) that is used to relieve the flicker impacts and maintain the voltage level. A weak voltage profile can not only reduce the power-quality services, but can also result in system instability in severe cases. The cybersecurity of EAFs is becoming a significant concern due to their cyber-physical structure. The reliance of SVC controllers on reactive power measurement and network communications has resulted in a cyber-vulnerability point for unauthorized access to the EAF, which can affect its normal operation. This paper addresses concerns about cyber attacks on EAFs, which can cause network communication issues in measurement data for SVCs. Three significant and different types of cyber attacks that are launched on SVC controllers—a replay attack, delay attack, and false data injection attack (FDIA)—were simulated and investigated. In order to stop the activities of cyber attacks, a secured anomaly detection model (ADM) based on a prediction interval is proposed. The proposed model is dependent on a support vector regression and a new smooth cost function for constructing the optimal and symmetrical intervals. A modified algorithm based on teaching–learning-based optimization was developed to adapt the ADM’s parameters during training. The simulation’s outcomes on a genuine dataset showed the strong capability of the proposed model against cyber attacks in EAFs.

Orbital angular momentum (OAM) multiplexing provides an efficient method to improve data-carrying capacity in various quantum communication protocols. It is a precondition to distribute OAM multiplexed quantum resources in quantum channels for implementing quantum communication. However, quantum steering of OAM multiplexed optical fields and the effect of channel noise on OAM multiplexed quantum resources remain unclear. Here, we generate OAM multiplexed continuous-variable (CV) entangled states and distribute them in lossy or noisy channels. We show that the decoherence property of entanglement and quantum steering of the OAM multiplexed states carrying topological charges l = 1 and l = 2 are the same as that of the Gaussian mode with l = 0 in lossy and noisy channels. The sudden death of entanglement and quantum steering of high-order OAM multiplexed states is observed in the presence of excess noise. Our results demonstrate the feasibility to realize high data-carrying capacity quantum information processing by utilizing OAM multiplexed CV entangled states.

Nondegenerate four-wave mixing (FWM) process based on a double-Λ scheme in hot alkali metal vapor is a versatile tool in quantum state engineering, quantum imaging, and quantum precision measurements. In this Letter, we investigate the generation of quantum correlated twin beams which carry nonzero orbital angular momentums (OAMs) based on the FWM process in hot cesium vapor. The amplified probe beam and the newly generated conjugate beam in the FWM process have the same and opposite topological charge as the seed beam, respectively. We also explore the FWM process operated in a nonamplifying regime where quantum correlated twin beams carrying OAMs can still be generated. In this regime, the FWM process plays the role of quantum beam splitter for the OAM of light, that is, a device that can split a coherent light beam carrying OAM into quantum-correlated twin beams carrying OAMs. More generally, our setup can be used as a quantum beam splitter of images.

With the object of optical sensor detects the position of the sun, the working principle of the sun position detection system based on four photosensitive devices was analyzed.The sensitive part of this type of sensors was analyzed with optimization. Silicon photocells were selected as optical elements . The main factors and interactions between them which affect the accuracy of the sensor were analyzed using the idea of orthogonal experiment and related software , the optimal combination for the size of the sensor structure was got.