A new algorithm based on the background field for red tide monitoring in the East China Sea

Remote sensing has been proven to be an effective means of monitoring red tides. The spectral information is an important basis for establishing a model to monitor red tides. The spectral curves of red tide events are analyzed and compared with multiyear monthly averaged spectral curves based on MODIS data from July 2002 to June 2012, as well as spectral differences at the same location during red tide presence and absence. A red tide monitoring algorithm is developed based on the background field to extract the red tide information of the East China Sea （ECS）. With the application of the algorithm in the ECS, the results reveal that the developed model can effectively determine the location of red tides, with good correspondence to the results from an official bulletin. This demonstrates that the algorithm can effectively extract the red tide information.

A numerical model study on multi-species harmful algal blooms coupled with background ecological fields

Based on systematized physical, chemical, and biological modules, a multi-species harmful algal bloom （HAB） model coupled with background ecological fields was established. This model schematically embod-ied that HAB causative algal species and the background ecological system, quantified as total biomass, were significantly different in terms of the chemical and biological processes during a HAB while the inter-action between the two was present. The model also included a competition and interaction mechanism between the HAB algal species or populations. The Droop equation was optimized by considering tempera-ture, salinity, and suspended material impact factors in the parameterization of algal growth rate with the nutrient threshold. Two HAB processes in the springs of 2004 and 2005 were simulated using this model. Both simulation results showed consistent trends with corresponding HAB processes observed in the East China Sea, which indicated the rationality of the model. This study made certain progress in modeling HABs, which has great application potential for HAB diagnosis, prediction, and prevention.

Influence of regional background stress fields on the spontaneous rupture of the major faults around Xiluodu dam,China

Simulations of the spontaneous rupture of potential earthquakes in the vicinity of reservoir dams can provide accurate parameters for seismic resilience assessment,which is essential for improving the seismic performance of reservoir dams.In simulations of potential spontaneous ruptures,fault geometry,regional stress fields,constitutive parameters of the fault friction law,and many other factors control the slip rate,morphology,and dislocation of the rupture,thereby affecting the simulated ground motion parameters.The focus of this study was to elucidate the effects of the background stress field on the nucleation and propagation of spontaneous ruptures based on the factors influencing potential M>7 earthquake events on the Leibo Middle Fault(LBMF)and the Mabian-Yanjing Fault(MB-YJF)in the Xiluodu dam(XLD)region.Our simulation results show that the magnitude of the regional background stress field plays a decisive role in whether a destructive earthquake exceeding the critical magnitude will occur.We found that the direction and magnitude of the regional stress significantly affect the range of rupture propagation on the fault plane,and fault geometry affects the spatial distribution of the rupture range.Under the same regional stress field magnitude and orientation,a more destructive,high-magnitude earthquake is more likely to occur on the LBMF than on the MB-YJF.

Density and temperature reconstruction of a flame-induced distorted flow field based on background-oriented schlieren(BOS) technique

An experimental system based on the background-oriented schlieren（BOS） technique is built to reconstruct the density and temperature distribution of a flame-induced distorted flow field which has a density gradient. The cross-correlation algorithm with sub-pixel accuracy is introduced and used to calculate the background-element displacement of a disturbed image and a fourth-order difference scheme is also developed to solve the Poisson equation. An experiment for a disturbed flow field caused by a burning candle is performed to validate the built BOS system and the results indicate that density and temperature distribution of the disturbed flow field can be reconstructed accurately. A notable conclusion is that in order to make the reconstructed results have a satisfactory accuracy, the inquiry step length should be less than the size of the interrogation window.

3-D finite element modeling for evolution of stress field and interaction among strong earthquakes in Sichuan-Yunnan region

Based on the latest achievement about activities of geological structure, a 3-D finite-element model containing four layers of upper crust, lower crust (two layers) and upper mantle is established in the paper. By repeated tests and revisions, the boundary conditions of the model are determined. And then the background stress field, the stress field caused by fault creep and the stress field triggered by strong earthquake in Sichuan-Yunnan region, as well as their dynamic variations are calculated. The results indicate that the latter earthquake often occurs in the area with positive Coulomb rupture stress change associated with the former one, the former earthquake has a triggering effect on the latter one to a certain extent, and strong earthquake often occur in groups under the background of high stress, which is of great significance for distinguishing seismic anomalies, as well as for improving the level of earthquake prediction.

Transverse Zeeman background correction method for air mercury measurement

By utilizing a natural mercury lamp, the transverse Zeeman background correction method, which is used for trace mercury measurement in air, is studied. In this paper, a natural mercury lamp is used as a light source, and is placed in a 1.78-T magnetic field. The lamp emits two linearly polarized light beams σ± and π of 253.65-nm resonance line, which are used as bias light and absorbing light, respectively. A polarization modulation system is used to allow σ± and π light beams to pass through alternately with a certain frequency. A multipath optical cell with 12-m optical path is used to increase optical distance. Based on the system described above, the influence caused by UV absorbing gases, such as NO2, SO2, acetone, benzene, and O3, is analyzed. The results show that it may reduce the detection limit when the concentrations of these gases exceed 83.4 ppm, 20.3 ppm, 142.3 ppm, 0.85 ppm, and 0.55 ppm, respectively. The detection limit of the system is calculated and can achieve up to 1.44 ng/m3 in 10 minutes. Measurements on mercury sample gas and air are carded out, and the measured data are compared with the data of RA-915 mercury analyzer （Russia）. The result shows that the correlation coefficient reaches up to 0.967. The experimental results indicate that the transverse Zeeman background correction method can be used to quantify trace mercury in air with high-precision.

基于GPR-LSTM的地震热红外背景场的构建方法

地震监测是一项非常重要且具有挑战性的任务,遥感技术的不断发展加强了在宏观尺度上对地球表面的监测能力。研究表明,地震前通常都会出现地表温度异常升高的现象,因此各种异常提取算法被应用于地震热异常研究中。其中,基于背景场的提取方法由于具有较强的机理解释性而受到广泛应用。然而,以往基于背景场的异常提取方法更多将背景场限定于某一固定阈值,忽略了受外界因素(非震)影响导致的地表温度的小范围正常波动。据此,文中提出了一种基于GPR-LSTM的地震热红外背景场的构建方法。该方法包括两大部分:震期年变基准场的建立、实际LST的残差波动范围计算及背景场的构建。基于MODIS地表温度产品,以2008年四川汶川和新疆于田地震为研究对象,使用所述方法对地震前兆热异常信息进行提取与分析,经过实验得出以下结论:1)地震热异常通常沿青藏高原的断层分布,这不仅证明了文中方法能够减弱地表温度数据中噪声的干扰,同时也证明该方法在热异常信息提取方面的有效性;2)地震年份的构造活动比非地震年份更加活跃,导致地表温度的异常增温更加明显;3)不同地震案例震前的热异常时空特征各不相同。

The Background Variation of Natural Source ELF and Its EM Abnormal Phenomena in Yunnan Earthquakes

In order to add earthquake monitoring methods and develop new method research,the ELF Network for Earthquake Monitoring selected 30 stations in the Capital Circle and the Sichuan-Yunnan region. Finding electromagnetic field background variation is the basis of distinguishing the seismic electromagnetic anomalies. This paper introduces the data acquisition and selection of the Shexian,Anqiu,Lijiang and Dali stations which have recorded for longer time with better data and are located on the similar latitude. Then we use the natural source electromagnetic field's auto-power spectrum to express the intensity of the electromagnetic field. By using power spectral data of many frequencies in the observation frequency band,after the data pre-processing and sliding average noising,the background variation of extremely low frequency stations and the range ability were acquired.Taking the Baoshan M5. 1 earthquake on October 30,2015 and Dali M5. 0 earthquake on May 18,2016 as examples,the authors analyzed the earthquake electromagnetic anomaly characteristic of ELF stations around the earthquakes.

基于雷达探测数据的尾涡危险区评估

针对尾涡危险区域的研究可以有效避免后机尾涡危险遭遇事件的发生,提出了一种基于激光雷达探测数据的尾涡危险区计算方法。根据雷达实测数据反演飞机尾涡的演化轨迹和速度环量;基于后机遭遇前机尾涡的空气动力学响应构建滚转力矩系数模型;考虑尾涡在实际场景下的演化情况,结合反演得到的尾涡特征参数,计算飞机遭遇尾涡时的滚转力矩并计算尾涡危险区。结果表明:基于激光雷达探测数据反演尾涡特征参数,左涡和右涡的位置、环量并不一致,据此结合滚转力矩系数模型计算得到的整体危险区域也具有不对称性,当单涡更稳定时,对应的危险区域也更大。以B738为后机,选取某一尾涡探测片段验证,对于涡心坐标位置为左涡(390 m,8.61°),右涡(435 m,8.85°)的尾涡,左涡、右涡的环量分别为256.83 m^(2)/s和223.35 m^(2)/s,左涡相对右涡实际划设的危险区覆盖范围更大,因此后机与前机左右尾涡的安全阈值区域不同,可据此对横向间隔做出不同调整,因此所提方法有利于为分析后机遭遇安全性、缩短尾流间隔提出重要参考。

磁场背景下具有手征化学势的PNJL模型下的手征相变

采用具有两个味道的PNJL模型研究了均匀磁场背景下的手征相变,特别是磁场对手征相变的临界手征化学势的影响.结果表明,磁场对手征对称性自发破缺具有催化作用,即临界手征化学势随着磁场增大而增大.夸克的组分质量随磁场增大,但它随手征化学势的变化不一定是单调的,在接近临界手征化学势时,夸克的组分质量会单调减小,直至发生手征相变.同时也讨论了体积对临界手征化学势的影响,发现在简化处理方式下,系统尺度的减小会导致临界手征化学势的明显增大.

基于现场可编程门阵列的水果识别系统设计

针对目前大多数水果识别系统实时性差和成本较高的问题,本文提出一种基于现场可编程门阵列(FPGA)的水果识别系统。整体硬件设计包含图像采集、检测识别和显示模块。软件部分通过图像采集平台将水果图像存储至双倍数据率同步动态随机存储器(DDR3)控制模块,进行图像灰度化处理,并创造性地提出背景帧差法对水果图像进行分割。通过融合水果颜色和几何特征,实现对水果数量、颜色和种类的识别。整个水果识别系统在不同光照下对常见水果进行了测试。实验结果表明,水果平均识别准确率达到93.25%,识别速度约为16.67 ms,FPGA硬件资源消耗率仅占28.02%,可以满足实时性需求。

基于等效磁路网络法的均匀正交磁场对环形磁芯等效电感的影响

电源中的磁性元件对外部磁场天然敏感,其工作特性直接影响电源的输出特性。实现背景磁场的建模是研究电源中磁性元件受强杂散磁场干扰问题的重要前提,但目前关注这一应用场景的相关研究较少,且常用的电磁场分析方法难以兼顾计算的精度和效率。基于等效磁路网络法提出了一种杂散磁场效应的分析方法,该方法将研究对象等效生成磁路单元,离散形成网络模型,并通过求解等效磁路系统方程得到模型的场量分布。以一款具体的环形铁氧体磁芯为例,利用等效磁路网络法计算了环形磁芯在直流激励和均匀正交磁场下的场量分布,分析了背景磁场对其等效电感的影响。通过对比等效磁路网络法与有限元法的计算结果,验证了该方法的准确性与高效性,且适用于电源受背景磁场干扰问题的分析。

人工智能背景下高校商务英语教学新型场域构建研究

随着人工智能技术的快速发展和应用,高校商务英语教学正面临着新的挑战和机遇。传统教学模式难以满足学生对实际商务实践能力的需求,且与人工智能技术融合的教学模式还存在改进空间。因此,探索在人工智能背景下构建高校商务英语教学新型场域具有重要意义,旨在促进学生学习体验的提升和专业能力的培养,为高校商务英语教学的创新和改进提供理论支持和实践指导。本研究旨在探讨人工智能背景下高校商务英语教学新型场域构建的策略和实践,以提升学生的语言实践能力和专业素养。

不同遗传背景亲本及其杂交种对田间出苗率的影响

为了研究细胞质不同亲本及其杂交种对田间出苗率的影响,以29个AL型不育系和25个恢复系为亲本材料配制了双列杂交组合,以“同母多父”和“同父多母”的方式,对杂交种和亲本的田间出苗率进行比较分析。结果表明,细胞质遗传背景不同的恢复系、保持系、杂交种之间田间出苗率差异不显著。杂交种与双亲的田间出苗率间呈显著正相关,田间出苗率高的亲本所配置杂交种田间出苗率表现出较高杂种优势。杂交种田间出苗率应该作为优异亲本的重要指标得到重视。

2022年台风“梅花”引起吉林地区暴雨天气过程的诊断分析

研究选择自动气象站资料、NCEP再分析资料等相关观测资料诊断分析2022年台风“梅花”在吉林引发暴雨的天气过程。结果显示:在本次天气出现之前,“梅花”引导气流沿副热带高压后部西南方向急剧向北移动。吉林省大多区域西风带出现小槽波动,在其后方增加了一些冷空气,给“梅花”系统暖湿空气带来较大影响,为本次极端降水天气创造了环流形势。

ARCADE 2 Spatial Roar, What Theory of Relation Reveals

The theory of Relation provides an explanation for the Arcade 2 excess. It assumes that the isotropic radio emission measured by the Arcade 2 Collaboration, which is 5 - 6 times brighter than the expected contributions from known extra-galactic sources, is the residue of an immense primitive energy of ordinary matter released by a relativistic bang almost 100 million years after the big bang, which gave the mass-energy the missing gravity to activate contraction. This relativistic bang, via a Lorentz energy transformation, would have released enormous energy held to be the source of the powerful radio noise detected by the NASA researchers. This transformation would have simultaneously triggered the formation of the first stars from dense gas and the reionization of less dense neutral gas. This departs from the idea that continuous reionization began after the formation of the first stars. We emphasize the importance of primordial magnetic fields, which would have generated significant density fluctuations during recombination and acted as a direct seed for cosmic structures. The first stars and galaxies were bathed in strong magnetic fields that gave rise to the radio microwave din (boom) discovered by Arcade 2. These intense magnetic fields alter the trajectory of charged particles zooming near the speed of light, triggering the space roar and emitting radiation that forms a synchrotron radio background. The theory of Relation offers an alternative to the Lambda-CDM cosmological model, which has become the standard model of the big bang, which leads straight to the vacuum catastrophe.

邢台震区应力场特征及M_(L)3.5以上地震的发震背景分析

邢台老震区构造背景复杂,发育多组断裂,属构造较不稳定地带,且区域中小地震频发。2017年至2021年发生6次M_(L)3.5以上地震,其中有两次M L4以上地震。本文基于搜集的震源机制解资料,反演区域现今地壳应力场,模拟震源机制与地壳应力场的关系,计算地壳应力场在地震发震断层面上的相对剪应力和相对正应力,分析地震的发震背景。结果表明,6次M_(L)3.5以上地震中,有2次震源机制节面接近应力场的最大剪应力节面,有4次震源机制节面远离应力场的最大剪应力节面。说明地震不是完全按照震源机制节面上具有最大剪应力的破裂方向发生,有时可能发生在某些薄弱带上。因此,在进行地震预测时,不能只关注最大剪应力破裂方向,还应多关注其边缘的地质薄弱带,这一结果可能会为后续分析该区域的地震危险性,研究地震孕育机制及动力学过程提供一定的参考依据。

基于轴对称喷流的背景纹影测量方法对比研究

背景纹影(BOS)是一种基于光线折射的非接触式流场测量技术,可以定量获得流场的密度信息。与层析技术结合的背景纹影层析技术(BOST)能够实现三维密度场重建。本文针对轴对称喷管,采用BOS方法测量获得了超声速喷流的二维密度分布,在轴对称假设下采用BOST方法重构了其三维密度场并与二维结果进行对比。研究表明,二维BOS将视线积分的流场信息进行平均,忽略了沿光路方向流场结构变化所带来的影响,BOST模型中包含多个角度的投影信息,更准确地重建了喷流的三维结构和高空间分辨率的密度场。

首都圈地区土壤气Rn,Hg,CO_2地球化学特征及其成因

对首都圈地区跨18条活动断裂的35条剖面进行了土壤气浓度和通量测量,结果显示:各测量剖面土壤气Rn,Hg和CO2的浓度平均值分别为3.2—45.0kBq/m^3,3.9—24.9ng/m^3和0.154%—2.175%;其通量平均值分别为3.8—152.1 mBq/(m^2·s),0.1—42.6ng/(m^2·h)和8.5—89.4g/(m^2·d).研究区土壤气Rn,Hg和CO_2的浓度和通量均呈东高西低的变化趋势,与首都圈地区由西至东应力水平增高、地壳厚度逐渐减薄、沉积层厚度增大、地震活动逐渐增强等趋势相对应,这表明首都圈地区土壤气的区域地球化学特征主要受控于上地壳物质结构、深部气体补给和地震活动,同时也受到自然环境及土壤类型的影响.

我国地震电磁卫星数据分析及应用研究进展

本文介绍了地震电磁卫星数据分析在中国地震电磁学方面的研究进展情况，其中包括卫星数据分析的整体思路的确定，以及具体在电离层正常背景分析，干扰因素影响，数据分析方法和震例研究结果。目前的应用研究表明，电离层各观测参量具有不同的季节性及区域性复杂的正常变化背景，对提取地震异常增加了很多困难。而震例研究反映震前确实存在一定程度的电离层异常，空间电磁异常信息具有短临性和区域性特征，但异常的重复性、空间分布的相似性检验及背景场理论模拟等方法还需要在今后的工作逐步加强。