Research on algorithm of borehole resistivity imaging method

Tradicionalna metoda istraživanja istosmjerne struje suočit će se s velikim izazovom kad se otkrije duboki, složeni geološki cilj. U tu svrhuje razvijena je metoda unaprijednog modeliranja i inverznog modeliranja otpora bušotine. U skladu s geološkim značajkama, postavljen je geološki model. Numerička simulacija pokazuje da je metoda otpora bušotine vrlo dubok, složen geo-model. Stoga ovo istraživanje daje novu ideju za istraživanje dubokog, složenog cilja geo-električnog modela.Traditional dc electrical exploration method will face great challenge when detecting deep, complex geologic target. With the purpose, forward modelling and inverse modelling method of borehole resistivity has been developed. According to the characters of geology, the geological model has been set up. The numerical simulation shows that borehole resistivity method is a very deep, complex geo-model. Therefore, this research provides a new idea for exploring deep, complex target of geo-electrical model

Modeling of whole-space transient electromagnetic responses based on FDTD and its application in the mining industry

Hidden, water-abundant areas in coal mines pose a serious threat to mine safety and production. Underground transient electromagnetic method (TEM) is one of the most effective means of detecting water-abundant areas in front of the roadway head. Traditional TEM theories and applications are interpreted mainly on the vertical component. In this study, multicomponent responses of TEM in underground roadways were modeled using the finite-difference time-domain method. Physical simulation was also used for advanced detection of TEM in the roadway. Both the numerical and physical simulation results show that the horizontal component is more sensitive to the location of water-abundant areas. The results of the joint interpretation with both horizontal and vertical components were verified in a practical coal mine application, indicating that it is feasible to use the horizontal component in interpreting TEM data. Thus, the horizontal component could serve as a new approach for coal mine TEM data processing and interpretation.The State Key Research Development Program of China (NO. 2017YFC0804401), in part by the China Postdoctoral Science Foundation (NO.110101/3445), and in part by the National Research Foundation, South Africa (RDYR160404161474).http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=9424hj2018Electrical, Electronic and Computer Engineerin

VPA mediates bidirectional regulation of cell cycle progression through the PPP2R2A-Chk1 signaling axis in response to HU

Cell cycle checkpoint kinases play a pivotal role in protecting against replicative stress. In this study, valproic acid (VPA), a histone deacetylase inhibitor (HDACi), was found to promote breast cancer MCF-7 cells to traverse into G2/M phase for catastrophic injury by promoting PPP2R2A (the B-regulatory subunit of Phosphatase PP2A) to facilitate the dephosphorylation of Chk1 at Ser317 and Ser345. By contrast, VPA protected normal 16HBE cells from HU toxicity through decreasing PPP2R2A expression and increasing Chk1 phosphorylation. The effect of VPA on PPP2R2A was at the post-transcription level through HDAC1/2. The in vitro results were affirmed in vivo. Patients with lower PPP2R2A expression and higher pChk1 expression showed significantly worse survival. PPP2R2A D197 and N181 are essential for PPP2R2A-Chk1 signaling and VPA-mediated bidirectional effect on augmenting HU-induced tumor cell death and protecting normal cells

Risk factors associated with postoperative respiratory failure after esophagectomy for esophageal cancer

Aim: Respiratory failure is common after esophagectomy for esophageal cancer (EC). This study aimed to identify the risk factors associated with postoperative respiratory failure following esophagectomy for EC. Methods: A single-center observational study from China was conducted on 262 patients with EC who underwent thoracoscopic esophagectomy between April 2014 and June 2016. The patients were divided into two groups: group I (respiratory failure) and group II (without respiratory failure). Demographic and perioperative variables, tumor-related factors, surgical factors, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and clinical course were compared between the groups. Univariable and multivariable logistic regression analyses were performed to assess the risk factors of postoperative respiratory failure after esophagectomy. Results: Among the 262 patients, 24 (9.2%) developed respiratory failure. Univariable analysis revealed several risk factors, including age, smoking, comorbidities, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), forced vital capacity (FVC), FVC percentage (FVC%), urine volume during surgery, and APACHE II score. Multivariable analysis showed that age, comorbidities of diabetes mellitus (DM), FVC%, urine volume during surgery, and APACHE II score were independent predictors of respiratory failure. Specifically, elderly patients (> 65 years) with comorbidities of DM, lower FVC%, higher urine volume during surgery, and elevated APACHE II score were found to be more susceptible to respiratory failure, resulting in prolonged hospitalization and increased healthcare burden. These findings emphasize the importance of considering these factors in the management and care of patients at risk of respiratory failure. Conclusions: As a common complication following esophagectomy for EC. Respiratory failure is significantly associated with age, comorbidities of DM, FVC%, urine volume during surgery, and APACHE II score in the dataset. The findings will contribute to the evaluation of the risk of respiratory failure and guide early intervention strategies in clinical decision-making

Improving Data Augmentation for YOLOv5 Using Enhanced Segment Anything Model

As one of the state-of-the-art object detection algorithms, YOLOv5 relies heavily on the quality of the training dataset. In order to improve the detection accuracy and performance of YOLOv5 and to reduce its false positive and false negative rates, we propose to improve the Segment Anything Model (SAM) used for data augmentation. The feature maps and mask predictions generated by the SAM are used as auxiliary inputs for the Mask-to-Mask (M2M) module. The experimental results show that after processing the dataset with the improved Segment Anything Model, the detection performance of YOLOv5 is improved with 99.9% precision and 99.1% recall. The improved YOLOv5 model has a higher license plate recognition accuracy than the original detection model under strong snowfall conditions, and the incidence of false-negative and false-positive is greatly reduced. The enhanced model can meet the requirement of accurate real-time recognition of license plates under strong snowfall weather conditions

坑井を用いた電気 ・電磁気探査法と石油貯留層の評価への適用に関する研究

INTRODUCTION / PRINCIPLE AND METHODOLOGY OF ELECTRIC POTENTIAL PROSPECTING METHODS / MODELING OF ELECTRIC POTENTIAL METHOD AND ANALYSIS OF RESPONSE CHARACTERS AS WELL AS ITS APPLICATIONS / NUMERICAL SIMULATION OF CROSS-WELL ELECTROMAGNETIC RESPONSE / APPLICATION OF POROSITY –FLUID SATURATION-RESISTIVITY RELATIONSHIP IN OIL RESERVOIR EVALUATION / CONCLUSIONSMade available in DSpace on 2012-10-01T06:12:20Z (GMT). No. of bitstreams: 2 eng2125.pdf: 13590088 bytes, checksum: 29433b65be4df03d4ac0618d4f8b01bc (MD5) eng2125_abstruct.pdf: 11950 bytes, checksum: d5a5a0e5e54c67feb7f48fa157fd63f3 (MD5)Submitted by 愛 遠藤 ([email protected]) on 2012-10-01T06:12:20Z No. of bitstreams: 2 eng2125.pdf: 13590088 bytes, checksum: 29433b65be4df03d4ac0618d4f8b01bc (MD5) eng2125_abstruct.pdf: 11950 bytes, checksum: d5a5a0e5e54c67feb7f48fa157fd63f3 (MD5)工学府_地球資源システム工学With the development of oilfields, the distribution of oil and water is becoming more and more complex. It is therefore very crucial for oilfield development to examine accurately the positions of the distribution of oil and water. The seismic method is the most important method for studying the underground geological structures and reservoirs. Whereas seismic surveys can detect the structures that may contain hydrocarbons with great accuracy, seismic methods are not suitable in order to investigate the distribution of oil and water within the reservoir during the period of oil production, because it is very difficult to make a distinction between oil and water within these structures by the seismic methods. However, electrical methods can overcome this problem due to its detecting information of reservoir resistivity. In addition, water and hydrocarbons have distinct different resistivity. Hence during the period of oilfield production for monitoring the reservoir, the electrical methods are indispensable to investigate changing of the reservoir by obtaining reservoir geophysical information. Especially, the information about resistivity of the reservoir should be analyzed. In this dissertation, two types of electrical methods have been discussed. One was direct current (DC) method and the other one was alternate current (AC) method. In order to calculate the oil saturation from the reservoir resistivity, the relationship among types of porosity, resistivity and fluid saturation should be considered. It is noteworthy that the Archie’s formula was actually established on the basis of pure sandstone with high-porosity and high-permeability. Besides, the application range of the Archie’s formula is valid when the several following conditions are true: (1) the matrix is an insulator or it is not conductive, (2) the distributions of porosities are homogeneous, (3) each fluid saturation of the porosities is also homogeneous, (4) all the fluids are mineralized rather than fresh water, (5) furthermore, electrical properties of the rock are isotropic. However, for low-porosity and low-permeability reservoir, the Archie’s formula will definitely confront a big challenge. Hence, it is attempted to use the new formula to describe the relationship among porosity, resistivity and fluid saturation in this dissertation

Detecting permafrost in plateau and mountainous areas by airborne transient electromagnetic sensing

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Transportation has become a key bottleneck which restricts economic development in Western China. However, during the construction of the western railway, the permafrost problem has plagued railway construction on the Qinghai–Tibet Plateau, and has not yet been resolved. Accurately identifying permafrost by geophysical method is the most effective means to solve this problem. However, the mountainous and plateau terrain in Western China impose huge challenges in collecting geophysical data. To address this issue, this paper proposes an airborne transient electromagnetic method to collect geophysical electromagnetic data to identify permafrost in the mountains and plateaus of Western China. Based on Maxwell’s equations, the forward model of the airborne electromagnetic was derived, and the finite element method was used to calculate the two-dimensional (2D) space electromagnetic responses of different permafrost geo-electrical models. Furthermore, a coupling function was constructed to estimate the distribution of the resistivity of the permafrost by the least-squares fitting algorithm. Comparison between inversion resistivity distribution and the geo-electrical model showed that the proposed airborne transient electromagnetic method was valid for exploring the permafrost in the mountains and the Qinghai–Tibet Plateau in Western China

Borehole Electromagnetic Method for Exploration of Coal Mining Goaf

Due to severe harms of goaf collapse, the goaf exploration and governance has become an urgent issue for protecting the normal life of local people. According to the coal mine geology, different geo-electrical models have been employed for the purpose of discovering the goafs. However, most existing methods require a large amount of computation consumption. In order to address this issue, a forward numerical simulation using the borehole electromagnetic method has been developed in this work to explore the coal mining goafs. The innovation of this method is that the computation consuming can be saved significantly. Numerical simulation demonstrates high effectiveness of the borehole electromagnetic method in coal mining goaf exploration. Therefore, this research provides a new idea for exploring the coal mine goafs by geophysical method

Maxwell-Equations Based on Mining Transient Electromagnetic Method for Coal Mine-Disaster Water Detection

Water-bearing geological structure is a serious threat to coalmine safety. This research focuses on detecting water-bearing geological structure by transient electromagnetic method. First, we introduce the principle of mining transient electromagnetic method, and then explain the technique of Finite Different Time Domain using in the transient electromagnetic method. Based on Maxwell equations, we derive the difference equations of electromagnetic field and study the responses of water-bearing geological structure using FDTD. Moreover, we establish the relationship between receiving electromagnetic field and geological information. The typical coal geological model of goaf-water is chosen to do the numerical simulation. Besides, we verify the availability of the method by numerical simulation using coal geological model. Finally, we use the method in the coalmine which is located in Linfen city in Shanxi province in China, and the detecting result is verified by drilling