Integrated interpretation of dual frequency induced polarization measurement based on wavelet analysis and metal factor methods

In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.

Practical calibration method for instantaneous polarization radar systems utilizing a metal sphere

A practical calibration method is proposed for instantaneous polarization radar systems.The method only needs one measurement by using a metal sphere.The distortions of system and the actual polarization scattering matrix（PSM）of target can be obtained.First,an instantaneous polarization radar system is presented.The system can obtain PSM by a single pulse echo.The dual-polarization antenna can transmit and receive two orthogonal polarization waves.The multilayer micro-strip patch antenna is adopted for this kind of radar system.Second,based on the multi-port network theory,the operation and system errors of instantaneous polarization radar system are analyzed.By making assumption on the cross-talk factors of antenna,distortion matrices of R and Tare derived.Finally,the calibration method based on instantaneous polarization measurement is introduced.Simulation results show the performance of this calibration method.The values of calibrated PSM are in agreement with the actual ones after calibration.

Solution of two-dimensional scattering problem in piezoelectric/piezomagnetic media using a polarization method

Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezomagnetic ＂comparison body＂ is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green＇s function, which is obtained using the Radon transform. The expression is further simplified under conditions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelectric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.

Power System State Estimation Solution With Zero Injection Constraints Using Modified Newton Method and Fast Decoupled Method in Polar Coordinate

如何保证零注入节点的注入功率在状态估计结果中严格为0是电力系统状态估计研究中的重要问题。在直角坐标下,由于零注入约束为线性约束,可使用修正牛顿法来有效地解决这一问题。因此,借鉴直角坐标下修正牛顿法的思路,提出了极坐标下的修正牛顿法和修正快速解耦估计。这些方法的计算流程与传统的极坐标下的牛顿法和快速解耦估计非常相似,计算速度与大权重法相当,同时能够保证零注入约束严格满足。仿真结果验证了所得结论。

Mathematical Description of Acousto-Optic Tunable Filter Orthogonal Polarizing Method

The transfer function of the optical splitting system of the acousto-optic tunable filter （AOTF） is deduced to be a reference to optical design. The characteristic matrix （ transfer function） of AOTF is used to describe quantitatively the characters of polarization elements in the orthogonal polarizing system. According to the characteristic matrix, the included angle of polarizer＇s transmission direction and polarization analyzer＇s transmission direction should be 90°. As a result the signal to noise ratio increased about 20 times though the light intensity was reduced to 54.3%,because both the transmittances of polarizer and polarization analyzer are 0. 74, which is an intrinsic character. The orthogonal polarizing method is an effective method to get rid of the influence of zero order light and improve the spectrum resolution and signal-to-noise ratio.

MEASURING PRECISION OF INDUCED POLARIZATION METHOD

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Direct method of finding first integral of two-dimensional autonomous systems in polar coordinates

A direct method to find the first integral for two-dimensional autonomous system in polar coordinates is suggested. It is shown that if the equation of motion expressed by differential 1-forms for a given autonomous Hamiltonian system is multiplied by a set of multiplicative functions, then the general expression of the first integral can be obtained, An example is given to illustrate the application of the results.

Improved Measurement Method of Circularly-Polarized Antennas Based on Linear-Component Amplitudes

An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement on axial ratio (AR) of CP antennas can be realized without phase information. However, the rotation sense of the co-polarization cannot be determined due to the absence of the phase information. Above problem is discussed here for the first time, and a solution is presented to determine the rotation sense of the co-polarization by using common auxiliary CP antennas. In addition, there will be some particular cases with large errors in actual measurement. Here a corresponding solution method is given. Finally, co-polarization and cross-polarization patterns can be further obtained from AR results. To verify this improved method, a self-developed CP microstrip array was measured. The measured results are in agreement with the simulated results, which prove this method is correct, effective and practical.

Exploration of High-Harmonic Generation from the CS2 Molecule by the Lewenstein Method in Two-Color Circularly Polarized Laser Field

The high harmonic generation (HHG) from the CS2 molecule in intense laser fields is investigated using the extended Lewenstein method. The initial state is the highest-occupied molecular orbital of the CS2 molecule, which can be well described by Gaussian wave packet using GAMESS-UK package. Compared with the case of the elliptical laser, the HHG can be extended in two-color circularly polarized laser field. The time-frequency analysis and classical electron trajectory as well as the ionization yield curve are also presented to further explain the underlying mechanism. After adding a static electric field on the z-direction, the single quantum path control is realized and the supercontinuum spectra are obtained. Moreover, an isolated 110 as pulse can be obtained by superposing the harmonics from 130th to 180th order.

三维激电法在黔西北某铅锌矿勘查中的应用

黔西北铅锌成矿区是贵州省重要的铅锌产地之一,区内发现的某超大型铅锌矿深部及外围被认为仍具较大找矿潜力。随着埋深加大,地质条件更复杂,通过地球物理方法探查直接或间接的矿致异常愈加被认可。为研究三维激电方法在黔西北铅锌成矿区的勘查效果,首先在典型矿床开展了方法有效性及装置参数试验,结果显示梯度四极加三极装置联合反演显示的高极化率(17~20 mV/V)、低电阻率(158~251Ω·m)与已知铅锌矿体空间位置对应较好,然后应用到外围空白区,圈定了高极化、低电阻激电异常,经钻孔验证为含黄铁矿及铅锌矿(化)地质体。表明通过低电阻率高极化率圈定含黄铁矿物地质体异常,结合地质分析,间接指示铅锌矿体空间位置是本区三维激电方法应用的思路,对地区同类型铅锌矿地球物理勘探具有参考意义。

长相关随机模型FBM对光伏发电短期预测

针对光伏发电功率具有较强的波动性、间歇性输出,光伏功率预测精度较低,且难于给出具体预测时间长度等问题,提出了一种长相关随机模型分数阶布朗运动(fractional Brownian motion,FBM),用于光伏功率预测。首先,采用重标极差法计算长相关(long-range dependence,LRD)参数-Hurst指数,Hurst指数用于判断光伏功率数据是否满足长相关性,并通过最大李雅普诺夫指数(Lyapunov)计算出模型最大可预测时间尺度;其次,采用随机微分法建立FBM光伏功率预测模型,同时估计FBM预测模型参数值;最后,选取澳大利亚沙漠知识太阳能中心(Desert Knowledge Australia Solar Center,DKASC)、美国国家可再生能源实验室(National Renewable Energy Laboratory,NREL)以及北京国能日新科技有限公司的光伏功率数据集,从不同的地理环境、不同的气候特征、不同的规模大小电站进行验证。仿真结果表明,该模型较传统的Kalman、LSTM模型具有更高的预测精度,可为光伏并网的稳定和安全运行提供更好的理论支持,对电网调度部门具有较高的参考价值。

基于相场法的极地船舶结冰再辉过程模拟

极地船舶结冰是空气或海水中的过冷液滴落到船上后形成的。过冷液滴中的结晶核形成后,晶核进一步凝固放热使液滴温度重新回到凝固点并形成冰水混合物的过程被称为再辉,这是冻结阶段的开始。使用相场法,对不同过冷度下结冰再辉过程进行模拟,研究再辉后的结冰形貌和冰相比例。结果表明,过冷度对再辉结果有一定影响,再辉过程中的枝晶生长速度先快后慢,再辉结束后的冰相比例随过冷度增大而增大,过冷度从30K增至45K时,冰相比例从11.92%增至29.17%。

激发极化法在水文勘探中的应用

地下水评价的对象是浅层地下水,根据前期搜集地形资料、水文资料、附近工程地质资料等,水文物探工作需要指导地质勘察孔布置,并节省勘探工作量,因此采用激发极化法作为主要物探方法。激发极化法可采用电阻率法的各种装置进行,在本次探测中主要采用四极对称装置,最终为地质勘探提供测区内潜水面水位高程范围,且推测出一处古河道范围,为水文勘探工作提供可靠依据,取得了较好的研究效果。

基于相对拟牛顿法的自卫式欺骗干扰抑制算法

自卫式欺骗干扰与目标信号高度相似,且二者的到达角完全相同,传统的主瓣干扰抑制算法难以对其进行抑制。针对该问题,文中在极化单输入多输出(PSIMO)雷达系统下,提出一种基于相对拟牛顿法的盲源分离算法。该算法利用干扰和目标的极化特性差异,通过构建重叠子阵结构计算出联合自相关矩阵,并采用相对拟牛顿法估计出分离矩阵,从而将目标和干扰信号分离在不同的通道上,实现干扰抑制作用。仿真实验结果表明,该算法能够有效抑制自卫式欺骗干扰,且在低信噪比(SNR)和密集干扰场景下依然具有良好的干扰抑制性能,当输入SNR为-10 dB时,输出的目标检测概率仍可以达到51.6%,拥有较强的鲁棒性。

多尺度电磁联合方法在贵州某磷矿深部岩溶探测中的应用

随着新能源行业的迅猛发展以及粮食需求的不断增多,深部磷矿资源开采迫在眉睫。贵州作为磷矿资源大省,品位高、矿层厚,具有很高的开采价值。但该地区呈现典型的喀斯特地貌特征,可溶岩总面积达12.88万km^(2),约占全省总面积的73%。开采过程中极易发生井喷、突泥等地质灾害,严重影响工程进度与开发成本,甚至造成人员伤亡。因此,探明地下岩溶发育情况对于磷矿开采工作十分重要。结合研究区地质条件以及磷矿埋藏深的特点,本文综合运用扩频激电法和可控源电磁法进行岩溶探测。两种方法优势互补,相互印证,通过对反演得到的电阻率剖面图进行定性分析,准确地圈定出岩溶发育区,为下一步磷矿开采工作提供参考,同时也为岩溶发育地区的物探工作提供有益的参考和借鉴。

综合物探在黔西北猪拱塘地区铅锌矿找矿中的应用

猪拱塘地区位于黔西北铅锌矿集区,地质构造复杂,找矿前景巨大,受地形和勘查技术方法限制,研究程度较低,严重制约了铅锌矿勘查工作。为查明猪拱塘地区铅锌矿成矿环境,预测成矿有利地段,在研究区开展了激发极化法和可控源音频大地电磁测量(CSAMT),圈定了激电异常,查明了深部地层结构和控矿断裂发育情况,结合区域地质资料和岩矿石物性特征,分析了综合物探异常特征,指导了钻探工程部署,发现了隐伏铅锌矿体。最后总结了猪拱塘地区铅锌矿体具有典型的高极化率、低电阻率的特点,不同倾向断裂的交叉复合部位是铅锌矿赋存有利位置。本文为黔西北地区铅锌矿勘查工作提供了参考依据和经验积累。

井中激电地-井方式三维阵列观测方法研究

中国浅表矿、易采矿资源日趋枯竭,迫切需要在现有矿山开展深部找矿,研究适用于深部找矿的地球物理勘探新方法具有重要意义。本文探讨研究了井中激电地-井方式三维阵列观测方法,借助连续电性介质模型异常电位三维有限元数值模拟方法,对不同地电模型模拟的视电阻率和视极化率响应进行了模拟分析。研究结果表明:该方法有效拓展了观测空间,携带目标体信息丰富,可以有效从不同点位和层位提取曲线数据和切片数据,通过绘制相应图件从而分析目标异常的空间分布特征。本文模型分析结果可以作为异常推断解释的参考依据。

基于机器学习的SIP数据砂岩型铀矿氧化-还原带识别研究

砂岩型铀矿成矿过程中,氧化-还原作用是实现铀富集成矿的重要作用之一,有效圈定深部氧化-还原过渡带范围能够对指示深部找矿提供重要线索。频谱激电法(SIP)利用氧化-还原带岩石电化学特性差异,基于柯尔-柯尔(Cole-Cole)模型可反演获得地下介质多个复电阻率参数。采用该参数特征组合开展改进的Kmeans聚类,通过无监督机器学习算法实现数据结果自动分类,从而达到划分砂岩型铀矿氧化-还原分带的目的。经验证地层分带识别结果与钻探剖面验证情况一致性较好,表明Kmeans++法能够有效识别SIP结果数据中蕴含的砂岩型铀矿氧化-还原分带信息,为铀矿勘探缩小找矿范围,指示下一步找矿方向提供参考。

极地高密度烧结雪层无侧限压缩离散元分析

从新雪变成老雪的过程叫作“烧结”,对雪层进行人工压实和烧结是建设极地机场跑道的主要方法,雪层烧结使雪颗粒间胶结尺寸增加,雪层强度增强。为探究人工压实烧结雪层在无侧限压缩荷载下的胶结接触破坏规律和承力机理,本研究采用三维离散元方法模拟了密实烧结雪层无侧限压缩试验,在室内试验结果基础上构建雪的胶结接触模型并标定接触参数,通过建立压实烧结雪离散元模型,进行了无侧限压缩加载模拟。模拟的结果验证了离散元模拟的有效性并表明:(1)在无侧限压缩下,密实烧结雪试样在剪切带区域发生集中胶结破坏,胶结断裂主要归因于接触在受拉状态下受剪;(2)冰雪颗粒的破碎会影响冰雪道面的抗剪强度,因此需要慎重考虑高应力对内摩擦角的影响。本研究将为极地地区通过压实烧结雪层简单现场试验预测其复杂应力路径下的力学特征提供科学支持。

指压法对肥胖模型大鼠脂肪组织巨噬细胞极化状态的影响

目的观察指压法对肥胖大鼠脂肪组织巨噬细胞极化状态的影响,探讨指压法对肥胖模型大鼠脂肪组织免疫炎症反应的作用。方法将35只SD雄性大鼠造模后,随机分为正常组、模型组、指压组,每组10只。予指压法进行推拿干预,10 min/次,共6周,并记录每周体质量。治疗结束后,检测肥胖指标(体质量、Lee′s指数),脂代谢指标(TC、TG、HDL-C、LDL-C);免疫组化法检测脂肪组织中的M1、M2型巨噬细胞特异性抗体CD11c、CD206;采用蛋白质免疫印迹(Western Blot)技术检测各组大鼠脂肪组织中M1型巨噬细胞标志物诱导型一氧化氮合酶(inducible NOS,iNOS)及IL-6蛋白的表达。结果与正常组相比,模型组体质量、Lee′s指数、血清TC、TG、LDL-C含量均显著升高、M1型巨噬细胞CD11c浸润升高、M2型巨噬细胞CD206浸润减少、M1与M2比值明显增大、iNOS及IL-6蛋白的表达水平显著升高(P<0.05或P<0.01)。与模型组相比,指压组大鼠体质量、Lee′s指数、血清TC、TG、LDL-C含量均显著下降、M1型巨噬细胞CD11c浸润表达量显著下降、M2型巨噬细胞CD206的表达量明显增高、M1与M2比值显著降低、iNOS及IL-6表达水平均显著下降(P<0.05或P<0.01)。结论指压法能抑制高脂饮食诱导的M1型巨噬细胞极化状态,从而达到抑制炎症的作用,调节肥胖状态。