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Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Large-loop fixed source device is an equipment of transient electromagnetic method (TEM) . It can be observed inside and outside the frame, with a large detection depth and high construction efficiency. However, limited by the traditional data processing method using the central loop device, the current large-loop fixed source device only observes the signal in a certain area in the center of the transmitting wireframe. Based on the superposition of electric dipoles, the accurate calculation of the electromagnetic field at arbitrary position inside and outside the transmitting frame was realized. Furthermore, the distribution and diffusion characteristics of the primary and secondary fields generated by the large-loop fixed source were analyzed. Then, the one-dimensional inversion of arbitrary point inside and outside the frame using the OCCAM algorithm was implemented, and the feasibility was verified by a layered model. The results show that the proposed method can accurately inverse the underground electrical structure at arbitrary point inside and outside the large-loop fixed source frame. Finally, the proposed method was applied to process the measured data from one airport in Jingzhou city of Hubei province, and the results are reliable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Earth Sciences & Environment is the property of Journal of Earth Sciences & Environment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present, most of the existing data processing software for TEM only aim at the loop source devices, and can not deal with the data of the electric source devices. With the wide application of SOTEM, it is urgent to develop a set of data processing software suitable for SOT EM. By solving the key techniques of one-dimensional forward modelling for arbitrarily transmitters-receivers, joint inversion of multi-component and multi-source data, inversion of data with induced polarization effect, quasi-2D lateral constrained inversion, et c., SOTEMsoft, a special software system for SOTEM data processing was developed. The system has the functions of data arrangement, image display, data pre-processing, model building, forward modelling, data inverse, drawing input and so on. The results of numerical simulation and field data processing show that SOTEMsoft has perfect function, high precision and efficiency of data processing, and can meet the actual production requirements in field. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Earth Sciences & Environment is the property of Journal of Earth Sciences & Environment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To investigate the protective effect of metformin on the kidney in type II diabetes mellitus (T2DM) by regulating the activity of poly (ADP-ribose) polymerase 1 (PARP-1) and investigate the mechanism of this effect. Methods Wistar rats were divided into normal group (n = 12), DN group (n = 12), DN + DPQ group (n = 12), DN + metformin group (n = 12) and DN + metformin + DPQ group (n = 12). After model establishment, biochemical parameters such as fasting glucose content, urea nitrogen content, creatinine content, and urine protein concentration were measured in each group of rats. HE staining and TUNEL staining were used to observe the renal pathology, Western blot was applied to detect the protein expression of PARP-1, iNOS, NFκB and caspase-3. The expression of inflammatory factors TNF-α and IL-1β was detected by ELISA, and the expression of 3-nitrotyrosine (3-NT) was determined by immunohistochemistry. Results (1) The biochemical indexes of rats in the three treatment groups decreased compared with those in the DN group, with the most obvious changes in the DN + metformin + DPQ group (P < 0.01); (2) The expression of PARP-1 in rats in the three treatment groups decreased compared to the DN group, with the most significant decrease in the DN + metformin + DPQ group (P < 0.05); (3) The pathological changes of kidney tissue and apoptosis of kidney cells in the three treatment groups were alleviatedcompared with the DN group, with the most significant decrease in the expression of DN + metformin + DPQ group; (4) The expression of inflammatory factors as well as the expression of NF-kB, iNOS and 3-NT decreased in the three treatment groups compared with the DN group, with the most significant decrease in the DN + metformin + DPQ group (P < 0.05). Conclusion Metformin plays a role in protecting the kidney under the high glucose environment caused by diabetes through regulating the expression of PARP-1, downregulating the expression of NF-kB in the DN model, inhibiting NF-kB/iNOS/NO pathway, inhibiting oxidative damage, and reducing inflammation. [ABSTRACT FROM AUTHOR]

Transient electromagnetic method ( TEM) has been widely used in the mineral resources detection and environment engineering exploration. Up to now, the most commonly used forward simulation methods for TEM response contain integral equation method, finite difference method, finite volume method and finite element method. With the more complex exploration conditions and the much higher detection accuracy demand, it's of importance to study the high-resolution three-dimentional simulations of TEM to further improve the data processing and interpretation technologies. The research progress on three-dimentional TEM forward simulations was introduced in detail. Besides, the key technologies of finite difference method, such as the construction of quasi-static difference equation, the loading of emission source and boundary conditions, were analyzed. The key problems of the finite element method, such as the space discretization, time discretization and the solving of large linear equations, were put foward. It is concluded that to provide theory support for high-resolution detection of TEM in three-dimentional forward simulation is required to solve the following problems: carrying out response calculations of the field source effect, complex topography problem, polarization effect related to near-field methods, realizing multi-source and multi-components TEM forward modeling of special application situation. [ABSTRACT FROM AUTHOR]

The traditional deterministic inversion algorithm relies heavily on the initial model, which is easy to fall into the local minimum and leads to the final inversion results seriously deviate from the real model. As a relatively new stochastic inversion algorithm, particle swarm optimization (PSO) algorithm has a strong ability to jump out of local minimum. However, there are still some problems such as premature convergence and slow convergence speed, which limit the development of algorithm for 2- or 3-dimensional electromagnetic inversion. In view of the above problems, quantum-behaved particle swarm optimization was proposed to replace the traditional particle swarm optimization, and the law of quant um motion in the potential well was introduced into the particle swarm optimization algorithm, so that the particles could appear in any position with probability distribution in the potential well, which could effectively overcome the premature convergence problem caused by the aggregation of population. In addition, the quasi-2D inversion algorithm was used to replace the traditional 2-dimensional inversion algorithm. As the parameter dimension of inversion model decreases, the number of local minima was greatly reduced, which significantly improves the convergence speed of particle swarm optimization. However, if the traditional regularization process is still used in the quasi-2D inversion of particle swarm optimization, the optimization of regularization parameters will waste a lot of computing resources. Combining with the important position of global optimal particles at each measuring point in quantum-behaved particle swarm optimization in the evolution of particle swarm, the ex-Trimmed method was introduced to realize fast lateral constraint inversion by parameter smoothing constraint of global optimal particle model between adjacent points. Finally, the quasi-2D inversion technique based on quantum-behaved particle swarm optimization algorithm was applied to the simulation data of airborne transient electromagnetic method with noise, and the final inversion results were in good agreement with the forward model. [ABSTRACT FROM AUTHOR]

The detection of thin layers has always been paid a lot of attention in geophysical prospecting, but previous researches mainly focus on the detection results of different geophysical methods while ignoring the influence of the observation parameters. The grounded-wire transient electromagnetic method ( TEM) was chosen to the thin layer detection, and the relationship between offset, observation time and detection capability was analyzed based on the lD forward modeling and the defined relative anomaly, which was used to reflect the detection capability of the TEM for thin layers. Hence, the way on how to choose proper observation parameters for fast and fine detection of thin layers was given. The results show that detection capability of transient electromagnetic method for thin layers becomes decreased linearly and then gradually tends to be stable with the increase of the offset, at the same time, the demanded observation time becomes longer, which is bad for actual field measurement. Besides, the decrease speed of detection capability becomes slower with the increasing of resistivity or buried depth. Therefore, it is concluded that adopting short offset in data collecting not only can improve the detection accuracy, but also can improve the detection efficiency. [ABSTRACT FROM AUTHOR]

Short-offset grounded-wire transient electromagnetic method (SOTEM) has considerably improved the signal intensity by using the form of near-source detection. The present researches on SOTEM responses are mainly based on lD models and explore the response characteristics and detection abilities of two components: electric field Ex and magnetic field H z, which are not conducive to the accurate exploration of complex targets. Based on the above-mentioned problems, a three- dimensional ( 3D) finite-difference time-domain ( FDTD) was employed to simulate the diffusion pattern of SOT EM field in strata and the influence of 3D anomalous body on the diffusion of SOTEM field. The results show that the positive extreme value area of electric field Ex component mainly appears nearby the transmitting source, and diffuses gradually downward with time; the positive extreme value area and negative extreme value area of electric field EY component are mainly located at two ends of the transmitting source, and diffuse gradually downward and outward with time; the electric field Ez component undergoes jump at strata boundary; the positive extreme value area and negative extreme value area of magnetic field H x component are respectively located at two ends of the transmitting source, and diffuse gradually downward and outward with time; the upper part and lower part of magnetic field HY component are negative value area and positive value area, respectively, indicating that HY component will also be affected by the return current; the extreme value area of magnetic field Hz component is mainly below the transmitting source, and gradually moves downward with time; for the 3D anomalous body, the sensitivity areas of electric field Ex and magnetic field HY components are rightly above the anomalous body, while the sensitivity areas of electric field EY and magnetic field Hx components are outside the anomalous body and distribute around it, and the sensitivity areas of magnetic field H z component are on both sides of the anomalous body (close to transmitting source, and distant from transmitting source, respectively). It shows that the five components of SOTEM field have different sensitivity areas to the 3D anomalous body, and different components should be observed in different areas. [ABSTRACT FROM AUTHOR]

Copyright of Forest Engineering is the property of Forest Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)