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Electrical Detection of Shale Gas Layers Based on Wide-Field Electromagnetic Method
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作者 Man Li-Xin Tan Zhang-Kun +3 位作者 Jia Jian-Chao Gu Zhi-Wen Yu Chang-Heng Yin Xue-Bo 《Applied Geophysics》 2025年第3期878-890,898,共14页
The drilling gas production situation indicates a certain correlation between the shale gas reservoir in the Sichuan Basin and the high and low changes in formation resistivity.These variations are observed in the fir... The drilling gas production situation indicates a certain correlation between the shale gas reservoir in the Sichuan Basin and the high and low changes in formation resistivity.These variations are observed in the first member of the Longmaxi Formation to the Wufeng Formation at the bottom of the Longmaxi Formation.Given this correlation and based on the logging electrical data,this study employs the wide-field electromagnetic method(WFEM)to experimentally detect the electrical characteristics of the deep shale gas target layer in the Yibin area of southern Sichuan.The study also tests the regularity and effectiveness of the electrical parameters for evaluating favorable areas of shale gas reservoirs.In terms of specific operation,the structural pattern of the study area is implemented based on the wide-field electromagnetic results and geological data for comprehensive analysis,which identifies the main hidden faults and their influence range on low resistance.The detailed spatial distribution of the upper Ordovician Wufeng Formation and the lower Silurian Longmaxi Formation in the target layer with a buried depth of 2000-5000m is described.This layer exhibits the characteristics of a continuous and stable distribution of organic shale.After verifying the subsequent electrical logging data,the electrical logging curve is found to be essentially consistent with the shape and trend of the wide-field resistivity curve.This consistency demonstrates the effectiveness of WFEM in detecting shale gas layers. 展开更多
关键词 wide-field electromagnetic method feasibility study Shale gas exploration Recognition accuracy structural pattern
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Non-contact wide-field viewing system-assisted scleral buckling surgery for retinal detachment in silicone oilfilled eyes 被引量:1
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作者 Su-Lan Wu Yi-Qi Chen +7 位作者 Li-Jun Shen Jian-Bo Mao Li Lin Ji-Wei Tao Huan Chen Shi-An Zhang Jia-Feng Yu Chen-Xi Wang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第4期761-766,共6页
AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.MET... AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.METHODS:Totally 9 patients(9 eyes)with retinal detachment in SO-filled eyes were retrospectively analyzed.All patients underwent non-contact wide-field viewing system-assisted buckling surgery with 23-gauge intraocular illumination.SO was removed at an appropriate time based on recovery.The patients were followed up for at least 3mo after SO removal.Retinal reattachment,complications,visual acuity and intraocular pressure(IOP)before and after surgery were observed.RESULTS:Patients were followed up for a mean of 8.22mo(3-22mo)after SO removal.All patients had retinal reattachment.At the final follow-up,visual acuity showed improvement for 8 patients,and no change for 1 patient.The IOP was high in 3 patients before surgery,but it stabilized after treatment;it was not affected in the other patients.None of the patients had infections,hemorrhage,anterior ischemia,or any other complication.CONCLUSION:This new non-contact wide-field viewing system-assisted SB surgery with 23-gauge intraocular illumination is effective and safe for retinal detachment in SO-filled eyes. 展开更多
关键词 non-contact wide-field viewing system scleral buckling silicone oil-filled retinal detachment
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Application of wide-field electromagnetic method for favorable target optimization in the Heishan granite geothermal area of Yunnan Province 被引量:1
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作者 Jie Li Honghu Zeng +2 位作者 Xiaoyong Lu Chao Xu Jingrui Chen 《Natural Gas Industry B》 2024年第1期74-82,共9页
The Heishan geothermal area is positioned above the sole Yunnane-Tibet high-temperature geothermal belt,where huge geothermal energy resources are available.Utilizing the characteristics of large exploration depth,ext... The Heishan geothermal area is positioned above the sole Yunnane-Tibet high-temperature geothermal belt,where huge geothermal energy resources are available.Utilizing the characteristics of large exploration depth,extensive coverage,and high precision of the wide-field elec-tromagnetic method,four survey lines were deployed,totaling 29.8 km,to enable a comprehensive analysis of the granite structure and fault distribution.The results indicate that the rocks within the area can be vertically divided into a granite basement and a fractured layer.Moreover,three different zones of resistivity were identified:the granite basement zone has a resistivity range of 2500-20000 U m,whereas the compressional shear zone and the secondary fault zone have a resistivity range of 750-2500 U m,and the extensional fault zone and the main fault zone have resistivity values below 750 U m.The Heishan-Hejian fault and the fault zone formed during its right-lateral strike-slip process,as well as the controlled area of the Qianmaihe fault,are all favorable targets.Of these,the Qianmahe fault possesses a larger-scale heat-conducting and water-controlling structure.In addition,in the secondary fault-controlled area extending to the west,the zone between F2’and F4 exhibits renewed tectonic activity,suggesting a greater potential for geothermal resources. 展开更多
关键词 Heishan geothermal area wide-field electromagnetic method Medium-deep geothermal Heat-conducting structure DESERT
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Application of a wide-field electromagnetic method to shale gas exploration in South China 被引量:7
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作者 杨学立 李博 +1 位作者 彭传圣 杨洋 《Applied Geophysics》 SCIE CSCD 2017年第3期441-448,462,共9页
In an effort to reduce the shale gas exploration risks and costs, we applied the wide-field electromagnetic method (WFEM), because of its strong anti-interference capability, high resolution, ability to conduct expl... In an effort to reduce the shale gas exploration risks and costs, we applied the wide-field electromagnetic method (WFEM), because of its strong anti-interference capability, high resolution, ability to conduct exploration at large depths, and high efficiency, to the Bayan Syncline in the South Huayuan block, Hunan Province. We collected rock samples and analyzed their resistivity and induced polarization (IP) and built A series of two-dimensional models for geological conditions to investigate the applicability of WFEM to different geological structures. We also analyzed the correlation between TOC of shale and the resistivity and IP ratio to determine the threshold for identifying target formations. We used WFEM to identify the underground structures and determine the distribution, depth, and thickness of the target strata. Resistivity, IP, and total organic carbon were used to evaluate the shale gas prospects and select favorable areas (sweet spots) for exploration and development. Subsequently, drilling in these areas proved the applicability of WFEM in shale gas exploration. 展开更多
关键词 wide-field electromagnetic method shale gas RESISTIVITY induced polarization total organic carbon
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Extracting useful high-frequency information from wide-field electromagnetic data using time-domain signal reconstruction 被引量:1
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作者 LING Fan YANG Yang +6 位作者 LI Gang ZHOU Chang-yu HUANG Min WANG Xin ZHANG Heng ZHU Yu-zhen SUN Huai-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第11期3767-3778,共12页
The wide-field electromagnetic method is widely used in hydrocarbon exploration,mineral deposit detection,and geological disaster prediction.However,apparent resistivity and normalized field amplitude exceeding 2048 H... The wide-field electromagnetic method is widely used in hydrocarbon exploration,mineral deposit detection,and geological disaster prediction.However,apparent resistivity and normalized field amplitude exceeding 2048 Hz often exhibit upward warping in data,making geophysical inversion and interpretation challenging.The cumulative error of the crystal oscillator in signal transmission and acquisition contributes to an upturned apparent resistivity curve.To address this,a high-frequency information extraction method is proposed based on time-domain signal reconstruction,which helps to record a complete current data sequence;moreover,it helps estimate the crystal oscillator error for the transmitted signal.Considering the recorded error,a received signal was corrected using a set of reconstruction algorithms.After processing,the high-frequency component of the wide-field electromagnetic data was not upturned,while accurate high-frequency information was extracted from the signal.Therefore,the proposed method helped effectively extract high-frequency components of all wide-field electromagnetic data. 展开更多
关键词 wide-field electromagnetic method crystal oscillator error time series signal resampling signal reconstruction
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Combined Application of Wide-Field Electromagnetic Method and Flow Field Fitting Method for High-Resolution Exploration: A Case Study of the Anjialing No. 1 Coal Mine 被引量:21
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作者 Jishan He 《Engineering》 2018年第5期667-675,共9页
The Anjialing No. 1 Coal Mine in Shanxi Province, China, contains a complicated old goaf and an unknown water distribution that hold high potential for serious water hazards. Due to poor detection resolution, previous... The Anjialing No. 1 Coal Mine in Shanxi Province, China, contains a complicated old goaf and an unknown water distribution that hold high potential for serious water hazards. Due to poor detection resolution, previous attempts have failed to determine the scope of the old goal and the water distribution in the mine by separate use of various exploration methods such as seismic method, direct current resistivity, audio magnetotellurics, controlled-source audio-frequency magnetotellurics, and transient electromag-netics. To solve this difficult problem, a combination of the wide-field electromagnetic method and the flow field fitting method with three-dimensional resistivity data inversion was applied to determine the precise scope of the goal and the locations where water is present, and to identify the hydraulic con- nection between the water layers so as to provide reliable technical support for safe coal production. Reasonable results were achieved, with all these goals being met. As a result, a mining area of nearly 4 km^2 has been released for operation. 展开更多
关键词 wide-field electromagnetic method Flow field fitting method GoalWater abundance High-resolution exploration
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Wide-Field Vibrational Phase Contrast Imaging Based on Coherent Anti-Stokes Raman Scattering Holography 被引量:1
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作者 吕永钢 纪子衡 +2 位作者 董大山 施可彬 龚旗煌 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期86-89,共4页
We propose and implement a wide-field vibrational phase contrast detection to obtain imaging of imaginary components of third-order nonlinear susceptibility in a coherent anti-Stokes Raman scattering (CARS) microsco... We propose and implement a wide-field vibrational phase contrast detection to obtain imaging of imaginary components of third-order nonlinear susceptibility in a coherent anti-Stokes Raman scattering (CARS) microscope with full suppression of the non-resonant background. This technique is based on the unique ability of recovering the phase of the generated CARS signal based on holographic recording. By capturing the phase distributions of the generated CARS field from the sample and from the environment under resonant illumination, we demonstrate the retrieval of imaginary components in the CARS microscope and achieve background free coherent Raman imaging. 展开更多
关键词 wide-field Vibrational Phase Contrast Imaging Based on Coherent Anti-Stokes Raman Scattering Holography
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Characterization of the current crowding effect on chip surface using a quantum wide-field microscope
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作者 Rui Zhao Ding Wang +3 位作者 Huan Fei Wen Yunbo Shi Jun Tang Jun Liu 《Chinese Optics Letters》 SCIE EI CAS CSCD 2024年第6期123-128,共6页
We characterize the current crowding effect for microwave radiation on a chip surface based on a quantum wide-field microscope combining a wide-field reconstruction technique. A swept microwave signal with the power o... We characterize the current crowding effect for microwave radiation on a chip surface based on a quantum wide-field microscope combining a wide-field reconstruction technique. A swept microwave signal with the power of 0–30 d Bm is supplied to a dumbbell-shaped microstrip antenna, and the significant differences in microwave magnetic-field amplitudes attributed to the current crowding effect are experimentally observed in a 2.20 mm ×1.22 mm imaging area. The normalized microwave magnetic-field amplitude along the horizontal geometrical center of the image area further demonstrates the feasibility of the characterization of the current crowding effect. The experiments indicate the proposal can be qualified for the characterization of the anomalous area of the radio-frequency chip surface. 展开更多
关键词 current crowding effect microwave field on chip surface quantum wide-field microscope nitrogen-vacancy center
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相干FDA雷达收发联合多波束方法
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作者 张军 许京伟 +3 位作者 王柯祎 廖桂生 李军 蔡兴雨 《系统工程与电子技术》 北大核心 2025年第5期1487-1494,共8页
针对相干频率分集阵列雷达距离/时间-角度依赖的信号收、发处理问题,提出一种基于角度依赖匹配滤波的频率分集阵雷达收发联合多波束设计方法。该方法可以同时实现等效发射数字波束形成和信号脉冲压缩匹配处理。且不同空间角度的雷达回... 针对相干频率分集阵列雷达距离/时间-角度依赖的信号收、发处理问题,提出一种基于角度依赖匹配滤波的频率分集阵雷达收发联合多波束设计方法。该方法可以同时实现等效发射数字波束形成和信号脉冲压缩匹配处理。且不同空间角度的雷达回波信号可以独立进行处理,通过联合接收数字波束形成技术,可以同时进行收发联合波束形成,实现同时多波束广域宽角覆盖,满足雷达广域搜索任务的需要。仿真实验证明了所提方法的有效性。 展开更多
关键词 相干频率分集阵列 角度依赖匹配滤波 收发联合波束形成 广域宽角覆盖
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基于红外-可见光双波段的扫描型宽视场成像方法
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作者 代少升 郑昭 +1 位作者 陈昌川 蒋大川 《半导体光电》 北大核心 2025年第5期884-891,共8页
针对目前红外成像设备中可见光与红外波段成像分辨率低、视场小以及图像位置映射关系不一致等问题,提出一种基于红外-可见光双波段的扫描型宽视场成像方法。该方法首先使用阵列传感器采集物体的可见光波段图像,使用单元红外探测器感应... 针对目前红外成像设备中可见光与红外波段成像分辨率低、视场小以及图像位置映射关系不一致等问题,提出一种基于红外-可见光双波段的扫描型宽视场成像方法。该方法首先使用阵列传感器采集物体的可见光波段图像,使用单元红外探测器感应目标的红外热辐射,并通过电机驱动,以线扫描方式实现红外波段成像;然后根据可见光像素均匀分布与红外像素等角度分布的特点,在像素世界坐标系上实现正圆切割映射;最后利用扫描角度温度模型对红外图像进行温度补偿。结果表明,所提方法可以有效同步的采集可见光与红外波段图像,使可见光与红外图像在长、宽视场角度上具有1∶1的映射比,对红外与可见光双波段成像推广应用具有参考意义。 展开更多
关键词 双波段 红外可见光 宽视场 温度补偿 扫描
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接枝改性XLPE绝缘材料宽场域下的空间电荷与电导特性
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作者 杨旭 程功 +4 位作者 张城城 杨佳明 李春阳 赵洪 王暄 《电工技术学报》 北大核心 2025年第21期6882-6893,共12页
为探讨接枝改性对交联聚乙烯(XLPE)电荷输运行为的影响,在宽电场和宽温度场范围内,该文以XLPE和引入深陷阱基团的接枝改性交联聚乙烯(GXLPE)为研究对象,测试其在不同温度、电场下的空间电荷与电导特性。结果表明,XLPE中的电荷输运行为... 为探讨接枝改性对交联聚乙烯(XLPE)电荷输运行为的影响,在宽电场和宽温度场范围内,该文以XLPE和引入深陷阱基团的接枝改性交联聚乙烯(GXLPE)为研究对象,测试其在不同温度、电场下的空间电荷与电导特性。结果表明,XLPE中的电荷输运行为基本遵循空间电荷限制电流(SCLC)理论,电荷输运特性随外施电场升高分为欧姆区、陷阱限制空间电荷限制电流(TL-SCLC)区和陷阱被充满的空间电荷限制电流(TF-SCLC)区。随着温度升高,电荷输运机制转变的阈值电场强度向低电场方向移动,TF-SCLC区XLPE中出现严重的电荷包迁移现象。接枝改性后,在测试范围内,GXLPE电导特性仅表现出欧姆区和TL-SCLC区,接枝形成的深陷阱即使在120 kV/mm和90℃的电-热联合场作用下依然能够有效地抑制载流子迁移,表现出稳定的电导电流抑制效果。 展开更多
关键词 交联聚乙烯 接枝改性 宽场域 空间电荷特性 电导特性
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辽东南河洼金矿地质特征及成矿模式
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作者 梁维天 李帝铨 +4 位作者 刘超 滕寿仁 王东波 王鹏 冯家新 《地质与资源》 2025年第2期159-167,147,共10页
河洼金矿位于华北克拉通东部的金成矿带中,地表有多条金矿化蚀变带,具有金矿床发育前提.由于没有有效的深部勘查手段,虽然进行了大量的勘查研究工作,但对该地区地质认识有限.本文在前人地质研究成果的基础上,结合广域电磁法及深部钻探成... 河洼金矿位于华北克拉通东部的金成矿带中,地表有多条金矿化蚀变带,具有金矿床发育前提.由于没有有效的深部勘查手段,虽然进行了大量的勘查研究工作,但对该地区地质认识有限.本文在前人地质研究成果的基础上,结合广域电磁法及深部钻探成果,梳理永宁盆地地层地质特征,对不同深度成矿物质进行综合分析,对河洼地区金矿成矿特征及成矿模式形成新的认识,认为深度1000 m左右的永宁组地层与下伏片麻岩接触界面及界面附近发育的张裂隙,甚至热液活动的所有部位均为有利成矿部位.根据已有的金矿化蚀变规模推断,该地区具有很好的金成矿前景. 展开更多
关键词 金矿床 广域电磁法 永宁盆地 成矿模式 辽宁省
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广域电磁法在辽东新房金矿深部勘查中的应用
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作者 梁维天 冯家新 +1 位作者 李帝铨 郑军 《物探与化探》 2025年第5期1061-1069,共9页
新房金矿位于辽宁东部金多金属矿集区内,从区域成矿规律和已有的勘查成果来看,新房金矿所在的鸭绿江断裂带南部具有较大的金矿资源潜力。随着勘查工作的进一步深入,有望发现更多的金矿体。但目前由于缺少有效的深部勘查手段,该金矿区进... 新房金矿位于辽宁东部金多金属矿集区内,从区域成矿规律和已有的勘查成果来看,新房金矿所在的鸭绿江断裂带南部具有较大的金矿资源潜力。随着勘查工作的进一步深入,有望发现更多的金矿体。但目前由于缺少有效的深部勘查手段,该金矿区进一步的勘探开发研究工作进度不明显,不能很好地揭示该地区岩性界面延深特征及断裂构造分布情况。因此,本文应用广域电磁法首次在该地区进行勘查,根据数据结果结合地质工程资料对3 km以浅的电性层位进行了厘定,查明了新元古界盖层的厚度,并推测出多条断裂带,结合现有的地质资料认为深1 km左右的低阻异常带为韧性剪切发育的伸展构造面,为辽东地区地质找矿模型的建立提供了有效的地球物理数据,对该地区地质矿产勘查具有较高的研究意义。 展开更多
关键词 广域电磁法 金矿 深部勘查 低阻异常
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频率域电磁法电场梯度视电阻率研究 被引量:1
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作者 罗志亮 汤井田 +1 位作者 周聪 肖晓 《石油地球物理勘探》 北大核心 2025年第1期243-252,共10页
频率域可控源电磁法(Controlled Source Electromagnetic Method,CSEM)相比大地电磁法具有抗干扰能力强、观测场值强度大等优势,在矿产资源、工程勘查等领域应用广泛。定义适当的视电阻率公式能更直观地反映地下介质的综合电性变化,视... 频率域可控源电磁法(Controlled Source Electromagnetic Method,CSEM)相比大地电磁法具有抗干扰能力强、观测场值强度大等优势,在矿产资源、工程勘查等领域应用广泛。定义适当的视电阻率公式能更直观地反映地下介质的综合电性变化,视电阻率定义的研究一直是电磁法理论研究的重要课题之一。文中基于水平电偶极子在均匀大地表面产生的电场的解析式,推导了水平电场分量Ex的频率梯度和空间梯度解析式,用其计算均匀大地地表场值梯度响应;同时,基于加权外推法计算一维电磁响应,并采用三次样条插值算法计算场值的差分。将电场梯度解析值与电场差分值进行对比,验证了频率梯度和空间梯度解析式的正确性。基于均匀半空间场值梯度等效层状介质场值梯度,采用数值迭代的二分法求解非线性方程得到电场梯度视电阻率。计算结果表明,文中所定义的视电阻率计算公式可以反映地电结构变化,用差分值代替场值梯度进行视电阻率计算能够达到精度要求;水平电场的空间梯度视电阻率可以像广域视电阻率一样在近区和远区分别收敛于一个接近模型底层和顶层电阻率的值,符合理论预期,但是频率梯度视电阻率测深曲线不收敛,无法正确反映地下介质的电性变化,不具备测深能力。 展开更多
关键词 可控源电磁法 场值梯度 广域视电阻率 频率梯度视电阻率 空间梯度视电阻率
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广域电磁法对深部岩体的识别及在找矿中的应用:以胶东龙口—土堆金矿区为例 被引量:2
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作者 蒋永芳 李欢 +4 位作者 颜晓华 张婷 魏兴亮 孟超 陈庆 《中南大学学报(自然科学版)》 北大核心 2025年第3期966-978,共13页
胶东龙口—土堆金矿床的成矿模式认为深部隐伏岩体的形态及规模对找矿具有重要意义。为了精确探测矿区深部隐伏岩体,拓展深部找矿空间,采用广域电磁法对9条剖面共计1340个测点进行地球物理勘探实验。通过对岩石标本进行物性测量,野外实... 胶东龙口—土堆金矿床的成矿模式认为深部隐伏岩体的形态及规模对找矿具有重要意义。为了精确探测矿区深部隐伏岩体,拓展深部找矿空间,采用广域电磁法对9条剖面共计1340个测点进行地球物理勘探实验。通过对岩石标本进行物性测量,野外实测数据进行系统处理、反演和分析,综合地质解译,建立矿区三维地质-地球物理模型。利用广域视电阻率变化特征建立矿区的地质体空间格架,对深部岩体和构造界线进行厘定,并对致矿异常进行定性分析。研究结果表明:广域电磁方法能有效地识别深部岩体和大型构造,钻孔揭露的深部岩体顶界面位置与广域探测位置较一致;广域电磁法对郭城断裂、后夼东断裂、史家断裂等大型构造具有较好的识别效果,并能有效反映矿化构造蚀变带走向和延深趋势。 展开更多
关键词 广域电磁法 深部勘探 成矿岩体 金矿床 胶莱盆地
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主动回波控制的阵列布局设计与优化
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作者 杨龙 王文杰 +2 位作者 李濠君 向粤 赵旭 《兵工学报》 北大核心 2025年第1期333-345,共13页
针对水下航行器覆盖层厘米级厚度与米级低频探测波长的尺度矛盾难题,通过超磁致伸缩换能器次级发射阵元研制及发射单元表面构型优化,基于相控阵的主动回波控制方法开展水下大试样主动回波控制效果的仿真评估。通过声学有限元模型数值仿... 针对水下航行器覆盖层厘米级厚度与米级低频探测波长的尺度矛盾难题,通过超磁致伸缩换能器次级发射阵元研制及发射单元表面构型优化,基于相控阵的主动回波控制方法开展水下大试样主动回波控制效果的仿真评估。通过声学有限元模型数值仿真与大型压力消声水罐中的试验数据对比,验证空间声场中3个位置的声压级与声压云图,并研究不同阵列布局在300~2000 Hz的低频带范围内6个频率点的声场一致性。研究结果表明:频率越高,形成的平面声场一致性越差;以方盘为阵元的阵列形成的平面声场一致性优于圆盘阵列;最优阵列布局可在10 m后形成较好的平面声场,配合发射单元的最优构型进一步改善主动回波控制下的声场均匀程度,以达到更好的控制效果。 展开更多
关键词 主动回波控制 主动发射单元 阵列布局优化 相控阵 声场一致性 低频大宽带
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MASTA和WFST大视场望远镜的窄带光学成像观测分析
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作者 徐霄 娄铮 +2 位作者 平一鼎 董云芬 郑宪忠 《天文学报》 北大核心 2025年第5期143-154,共12页
在小焦比的光学系统中,窄带滤光片的光学性能会受到望远镜的光学系统以及光线入射角的显著影响.从视场中心至视场边缘,入射角的偏转逐渐增大,导致窄带滤光片出现中心波长蓝移,带通增宽以及最大透过率衰减.针对WFST (Wide Field Survey T... 在小焦比的光学系统中,窄带滤光片的光学性能会受到望远镜的光学系统以及光线入射角的显著影响.从视场中心至视场边缘,入射角的偏转逐渐增大,导致窄带滤光片出现中心波长蓝移,带通增宽以及最大透过率衰减.针对WFST (Wide Field Survey Telescope)与MASTA (Multi-Application Survey Telescope Array)望远镜开展窄带巡天观测的需求,定量分析不同窄带滤光片中心波长和带通随视场半径的变化.WFST的焦比F/2.49,轴外最大入射角为13.27°.在最大偏转处,中心波长分别为395 nm与656 nm的窄带滤光片的最大中心波长蓝移0.78%,10 nm和1 nm带通将分别增加2.67%和41.80%.最大透过率衰减系数分别为80.00%与74.50%.MASTA望远镜焦比为F/1.74,轴外最大入射角为18.48°.在最大偏转处,中心波长分别为395 nm与656 nm的窄带滤光片的中心波长将蓝移2.70%,其10 nm与1 nm带通的展宽将分别达到4.20%和81.70%,最大透过率衰减系数分别为80.00%与63.90%.未来基于WFST和MASTA开展发射线或吸收线的窄带观测,需系统考虑中心波长蓝移和带通变宽的影响. 展开更多
关键词 望远镜 仪器:滤光片 技术:测光 大视场巡天
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宽视场高分辨率光学系统的设计与优化
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作者 郭晓松 万云龙 +2 位作者 杨童 杨磊 谢洪波 《红外与激光工程》 北大核心 2025年第6期206-217,共12页
光学成像技术被广泛应用于军事、航天等领域,随着加工技术的发展,宽视场高分辨率成像成为主要应用需求。以反远摄结构作为基础,基于赛德尔像差理论,通过光阑光线入射角度控制约束,建立了一种宽视场高分辨率光学系统的初始结构。同时,以... 光学成像技术被广泛应用于军事、航天等领域,随着加工技术的发展,宽视场高分辨率成像成为主要应用需求。以反远摄结构作为基础,基于赛德尔像差理论,通过光阑光线入射角度控制约束,建立了一种宽视场高分辨率光学系统的初始结构。同时,以高阶像差约束控制作为进一步优化方向,设计了一种单孔径宽视场高分辨率成像光学系统。设计的系统视场角为70°,各视场调制传递函数(Modulation Transfer Function,MTF)曲线接近衍射极限,中心视场衍射MTF在550 lp/mm处优于0.2,系统成像质量良好,各项指标满足设计要求,实现了宽视场、高分辨率设计。 展开更多
关键词 光学设计 宽视场 高分辨率 像差优化 Zernike像差
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改进蜣螂优化LSTM的广域电磁去噪方法及应用
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作者 张贤 邓茂林 +2 位作者 李帝铨 刘业成 胡艳芳 《地球物理学进展》 北大核心 2025年第4期1577-1587,共11页
针对广域电磁法(Wide Field Electromagnetic Method, WFEM)受噪声影响而导致数据质量低与探测效果不理想的问题.本文提出改进蜣螂优化(Improved DBO, IDBO)长短期记忆网络(Long Short Term Memory, LSTM)的广域电磁去噪方法及应用.首先... 针对广域电磁法(Wide Field Electromagnetic Method, WFEM)受噪声影响而导致数据质量低与探测效果不理想的问题.本文提出改进蜣螂优化(Improved DBO, IDBO)长短期记忆网络(Long Short Term Memory, LSTM)的广域电磁去噪方法及应用.首先,利用空间金字塔匹配(Spatial Pyramid Matching, SPM)混沌映射、可变螺旋策略、Levy飞行机制、自适应t分布变异扰动策略改进蜣螂优化算法.然后,利用均方差作为IDBO算法的适应度,实现LSTM算法的超参数寻优.最后,将基于IDBO-LSTM的方法应用于广域电磁数据去噪中.实验表明,IDBO的寻优能力明显优于其他智能优化算法,优化后的LSTM算法在广域电磁数据去噪精度上明显地高于概率神经网络和LSTM算法的效果,处理后的广域电磁数据质量得到显著提升,电场曲线形态更为平稳,本文所提方法能为电磁法反演解释提供技术支持. 展开更多
关键词 广域电磁法 改进蜣螂优化算法 长短期记忆网络 去噪
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基于宽频正弦电场空间电荷响应的LDPE老化状态评估方法研究
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作者 谢丹阳 吴建东 +2 位作者 王俏华 罗响 尹毅 《中国电机工程学报》 北大核心 2025年第16期6526-6534,I0032,共10页
通过不同老化状态低密度聚乙烯(low density polyethylene,LDPE)试样在宽频正弦电场下的空间电荷响应分析,结合理化、电导及介电谱特性,研究LDPE老化状态评估新方法。实验所用正弦电场频率范围为0.5 mHz~10 kHz,电场幅值为10 kV/mm。结... 通过不同老化状态低密度聚乙烯(low density polyethylene,LDPE)试样在宽频正弦电场下的空间电荷响应分析,结合理化、电导及介电谱特性,研究LDPE老化状态评估新方法。实验所用正弦电场频率范围为0.5 mHz~10 kHz,电场幅值为10 kV/mm。结果表明:0.5 mHz~10 kHz电场频率范围内,LDPE内部平均相位体电荷密度随电场频率的变化呈“Z”字曲线变化趋势,低频下空间电荷积累量较多,高频下空间电荷积累量较少,该现象可能与低频电场的有效作用时间增加导致电荷注入量增多有关。高频电场下随电场频率的降低,老化0 h试样内部电荷量波动幅度较小,老化12 h及24 h试样内部电荷量逐步增多,推测该现象与老化12 h及24 h试样中离子电荷与注入电荷数目增多有关。随着老化程度的加深,同一电场频率下试样内部电荷积累量增多;未老化试样的空间电荷密度曲线在电场频率为10 Hz处出现转折,老化试样的转折阈值频率fc随老化程度的加深而减小。推测该现象与老化后试样大分子结构破坏,电荷注入势垒降低、电荷更易注入有关。宽频电场下LDPE材料注入电荷阈值频率fc可作为其老化状态评估参量。 展开更多
关键词 聚乙烯 老化 宽频电场 空间电荷 状态评估
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