ALOS-2 PALSAR-2的干涉相干性分析--以黄河上游地区为例

作为目前仅有的L波段星载SAR系统,PALSAR-2在国土资源调查和地质灾害监测方面有着广泛和独特的应用潜力。自其发射运行以来,它的数据质量成为用户们广泛关注的焦点。对于涉及雷达干涉测量的应用来说,干涉相干性是SAR数据最重要的质量评价指标之一。本文选取了覆盖黄河上游山区的PALSAR-2与PALSAR各一对影像,开展了干涉处理实验分析。本文提出采用相干分解技术,可以抑制几何去相干的影响,并从地物类型和地形坡度两个方面,分析比较它们的相干性分布差异,同时,给出了黄河上游地区的差分干涉初步结果。实验结果表明,在地形起伏较大的地区,相似观测模式获取的PALSAR-2数据的相干性通常优于PALSAR数据,干涉性能有显著的提升。同时,PALSAR-2差分干涉图在拉西瓦水电站果卜岸坡坡体上探测到了清晰的形变条纹,在滑坡体形变监测方面展现出巨大的应用潜力。

利用Sentinel-1和ALOS-2数据探测茂县中部活动滑坡

基于ALOS-2和Sentinel-1两种不同波长的遥感卫星影像,采用合成孔径雷达差分干涉测量技术(differential interferometric synthetic aperture Radar,DInSAR)两轨法和Stacking方法圈定四川省茂县中部正在发生地表形变的活动滑坡并分析了滑坡的运动特征。首先,针对ALOS-2卫星时间基线长、影像数据量少的问题,采用两轨法DInSAR进行滑坡形变探测;其次,基于短时间基线的多景Sentinel-1数据,采用Stacking方法探测滑坡形变;最后,综合分析两种数据集的形变速率结果,圈定四川茂县中部的潜在滑坡区域。结果表明,茂县白布村等地的疑似活动滑坡具有明显地表形变,雷达视线向形变速率最大绝对量达到200 mm/a;结合光学影像特征和已有历史调查资料,圈定了8个活动滑坡,两种数据的探测结果在其中7个活动滑坡处的空间分布能互相对应,对6个活动滑坡进行了野外调查,发现了地面变形迹象。结果表明,采用少量长波段ALOS-2影像和DInSAR两轨法,能够在具有一定植被覆盖度的山区探测到较为明显的滑坡地表形变;应用C波段的Sentinel-1影像时,则需要积累连续的多景数据,并应用时序分析方法,此时其探测效果比采用ALOS-2影像的两轨法效果更佳。

Relationship between Turbid Water and Coral Damage Distribution Using ALOS AVNIR-2 Images and Diving Survey Data Immediately after the Heavy Rain Disaster of the Amami-Oshima Island, Japan

To understand the relationship between turbid water and coral damage caused by the heavy rain disaster at the end of October 2010 in Amami-Oshima, Kagoshima Prefecture, Japan, turbid water and coral damage distribution monitoring was attempted using satellite imagery and a diving survey immediately after the disaster. ALOS AVNIR-2 images (spatial resolution: 10 m) on October 6 (before the disaster), October 24, October 30, and October 31 (after the disaster) were obtained as satellite data in 2010. The red-silt deposition index (RSI) map based on the method by Nadaoka and Tamura (1992) was also created. Moreover, a diving survey was conducted via the spot check method on December 18, 2010. As a result, comparison between the high turbidity (RSI) areas estimated using AVNIR-2 data and the coral damage areas judging from the field survey was considered relatively light. It is shown that satellite data such as AVNIR-2 can be a powerful tool to monitor damage distribution of coral reefs after heavy rain.

Estimation of Tropical Forest Structural Characteristics Using ALOS-2 SAR Data

The potential of ALOS-2 SAR data for the estimation of tropical forest structural characteristics was assessed in Vietnam by collecting forest inventory data. The effect of polarization and seasonality of the SAR data on the estimation of forest biomass was analyzed. The combination of HH, HV, and HH/HV polarizations using multiple linear regression did not improve the estimation of biomass compared to using the HV channel independently, as the HH and HH/HV variables were not statistically significant. The dry season HV backscattering intensity was highly sensitive to the biomass compared to the rainy season backscattering intensity. The SAR data acquired in the rainy season with humid and wet canopies was not very sensitive to the biomass. The strong dependence of the biomass estimates with the season of SAR data acquisition confirmed that the choice of right season SAR data is very important for improving the satellite based estimates of the biomass. The validation results showed that the dry season HV polarization could explain 54% variation of the biomass.

Enhanced Urban Sprawl Monitoring over the Entire District of Rome through Joint Analysis of ALOS AVNIR-2 and SENTINEL-2A Data

Based on the continuation of our past study, the present analysis is conducted to examine recent effects of the urbanization process occurring over the entire district of Rome. Overlays of ALOS AVNIR-2 and SENTINEL-2A satellite images, collected over a 6 years period, were validated via Geographic Information System (GIS) techniques, in a particular procedure applied to urban land and agricultural transformations. The use of Copernicus SENTINEL-2A imagery has improved the previous results on urban processes, by reducing the uncertainty of the discrimination of land cover classes and facilitating the photo-interpretation. Statistical analysis was performed via the Urban Area Profile index in order to quantify the sprawl phenomenon, by defining several landscape metrics. This work, to be enriched in the future by means of complementary information available from Copernicus radar sensors, like the one onboard Sentinel-1, completes the series of observations on land use published by the Italian National Institute for Environmental Protection and Research, which stopped back in 2008.

ALOS-2数据成像条件对地灾形变区探测的影响分析

InSAR技术是探测地面形变的重要手段。然而利用InSAR技术对地面形变进行探测过程中极易受到各类去相干源的影响,其中成像条件是引起去相干最重要的因素之一。成像条件主要包括时空基线、波长、入射角、升降轨和地表粗糙度、介电特性、大气条件等。本文定量分析了不同拍摄条件对形变区探测的影响,并采用四川茂县的31景ALOS-2数据进行了试验分析,影像共构成106个有效干涉对。试验结果表明,当空间基线小于107 m时,60%以上的数据可成功探测到形变;时间基线越大,能够探测到的形变区越少,两者呈幂函数关系;其他成像条件对形变区探测也会产生不同的影响。因此在形变探测过程中,应该在确保相干性的前提下采用尽量短的空间基线,同时确保合适的时间基线,并综合考虑其他成像条件的影响。本文为成功探测形变区提供了基本的技术指标。

Evaluating the Extraction Approaches of Flood Extended Area by Using ALOS-2/PALSAR-2 Images as a Rapid Response to Flood Disaster

Flash floods are recurrent events around the Japan region almost every year. Torrential rain occurred around Kanto and Tohoku area due to typhoon No. 18 in September 2015. Overflowing of the Kinugawa River led to river bank collapse. Thus, the flood extended into Joso City, Ibaraki Prefecture, Japan. ALOS-2/PALSAR-2 was the fastest satellite to record this flood disaster area. A quick method to extract the flood inundation area by utilizing the ALOS-2/ PALSAR-2 image as a rapid response to the flood disaster is required. This study evaluated three methods to extract the flood immediately after the flood occurring. This study compared the extraction approaches of flooded area by unsupervised classification, supervised classification and binary/threshold of backscattering value of flood. The results show that unsupervised classification and supervised classification are overestimated. This study recommends the binarization of the backscattering value to extract the extended flood area. This method is a straight forward approach and generates a similar distribution with the field survey by using the aerial photo with high accuracy (94% of kappa coefficient). We utilized slope map which derived from DEM data to eliminate the overestimated area due to shadowing effect in SAR images.

Seasonal Effects of Backscattering Intensity of ALOS-2 PALSAR-2 (L-Band) on Retrieval Forest Biomass in the Tropics

This research has used the L-band radar from ALOS-2 PALSAR-2 and field work data for evaluation of seasonal effects of backscattering intensity on retrieval forest biomass in the tropics. The effects of seasonality and HH, and HV polarizations of the SAR data on the biomass were analyzed. The dry season HV polarization could explain 61% of the biomass in this study region. The dry season HV backscattering intensity was highly sensitive to the biomass compared to the rainy season backscattering intensity. The SAR data acquired in the rainy season with humid and wet canopies were not very sensitive to the in situ biomass. Strong dependence of the biomass estimates with season of SAR data acquisition confirmed that the choice of right season SAR data is very important for improving the satellite based estimates of the biomass. This research expects that the results obtained in this research will contribute to monitoring of the quantity and quality of forest biomass in Vietnam and other tropical countries.

PI/AlO(OH)-SiO_2纳米杂化薄膜的制备及热性能、电性能分析

以聚酰亚胺作为高聚物反应基体,通过正硅酸乙酯(TEOS)和异丙醇铝的水解缩合反应,使之和聚酰胺酸发生溶胶-凝胶反应,从而制备出不同比例Al O(OH)-Si O2的聚酰亚胺杂化薄膜.利用原子力显微镜、热失重分析、介电谱和击穿试验对其表观形貌和热性能、电性能进行表征和测试,考察结构与性能之间的关系.

联合ALOS-2和Landsat 8的绿洲土壤水分反演模型研究

机器学习和多源数据融合是土壤水分反演研究的热点方向,但对L波段合成孔径雷达(synthetic aperture radar,SAR)数据的研究较少。以额济纳绿洲为研究区,利用ALOS-2 PALSAR-2和Landsat 8影像提取雷达和光学特征参数,通过参数重要性评分进行特征筛选,采用随机森林方法建立基于雷达、光学以及雷达-光学特征参数协同的土壤水分反演模型,对比模型精度,反演绿洲土壤水分。结果表明,与C波段相比,L波段SAR数据对干旱荒漠绿洲区土壤水分含量敏感性更高;雷达特征参数中重要性较高的为表面散射和体散射分量,二面角散射和螺旋体散射分量相对偏低;光学特征参数中植被供水指数重要性最高,增强型植被指数重要性最低。雷达特征参数方案最优模型决定系数R^(2)、均方根误差(root mean square error,RMSE)分别为0.67、2.16%,光学特征参数方案模型精度普遍较低且精度相当,R^(2)、RMSE分别为0.5、2.47%;雷达-光学参数协同反演的最优模型R^(2)、RMSE分别为0.72、1.99%,相比单一数据源,R^(2)分别提升7.46%、38.4%,RMSE分别降低8.54%、22.6%。研究证明,基于多源数据融合的随机森林模型在干旱荒漠绿洲区具有较高的预测精度和良好的适用性。

Na_4Ca_3(AlO_2)_(10)∶Eu^(2+),Mn^(2+)荧光粉的发光特性

采用高温固相法,制得一种新型荧光粉Na4Ca3(AlO2)10∶Eu2+,Mn2+。样品的结构和发光性质分别由X射线衍射谱和荧光光谱来表征。在Na4 Ca3(AlO2)10∶Eu2+的激发光谱中出现了Eu2+的f-d跃迁吸收带;在发射光谱中,出现蓝光发射,峰值位于441 nm。当在Na4Ca3(AlO2)10∶Eu2+中掺杂Mn2+时,发生了Eu2+→Mn2+的能量传递,在542 nm处出现了Mn2+的发射峰。在Na4 Ca3(AlO2)10∶Eu2+,Mn2+中,随着Mn2+浓度的增加,Eu2+粒子的发射强度减弱,而Mn2+粒子的发射强度增强,且Eu2+离子发射的衰减时间缩短,同时色度由蓝光移向白光。

Fe2+、AlO2-双水解反应的实验初探

基于一道关于离子共存的高考题目设计了对比实验,比较了Fe^2＋与Fe^3＋两者水解反应的差异。实验结果表明,Fe^2＋能够与AlO2-等离子发生双水解反应,同时还可能伴随着其他反应的发生,反应类型比较复杂。根据AlO2-的微观结构与性质,分析和讨论了其双水解反应的特性,指出不能在碱性条件下大量共存的离子均不能与AlO2-大量共存。

硅铝酸盐基底材料中Dy3Al2（AlO4）3的拉曼光谱及其荧光光谱特征研究

采用高温固相法合成不同浓度Dy元素掺杂的以硅铝酸盐为基底的荧光材料。通过X射线衍射物相分析可知,其主要物相组成中含有Dy3Al2(AlO4)3。通过拉曼光谱分析可知,在该体系中,874.5 cm^-1处振动峰与Dy和铝氧四面体之间伸缩振动相关,随着Dy掺杂量的增加,其拉曼峰强度呈现先增后减的变化规律;另外429.9 cm^-1处测得的振动峰与Dy和铝氧四面体结构之间的弯曲振动相关。随着Dy掺杂量的增加,拉曼振动峰强度,荧光分光光度计测得的荧光光谱以及拉曼光谱仪测得的光致发光光谱的峰强均呈现先增后减的变化规律。该体系中Dy元素与铝氧四面体匹配数量逐渐增加,当Dy掺杂量超过一定极限值时,体系内发生浓度猝灭,导致荧光性能下降。与Tb元素掺杂相比,两种体系材料的拉曼光谱峰形有很大的相似性,又存在细微差异。其中Tb元素掺杂体系材料的拉曼振动峰处于870.0和408.0 cm^-1处。两种不同元素掺杂的荧光材料其荧光强度变化规律具有一致性,表明稀土元素与铝(硅)氧四面体匹配数量是决定材料荧光性能的关键因素。

Accuracy Assessment of Alos W3d30, Aster Gdem and Srtm30 Dem: A Case Study of Nigeria, West Africa

Digital Elevation Models (DEMs) depict the configuration of the earth surface and are being applied in many areas in earth and environmental sciences. In this study, the accuracy of the Advanced Land Observing Satellite World 3D Digital Surface Model version 2.1 (ALOS W3D30), the Shuttle Radar Topography Mission Digital Elevation Model version 3.0 (SRTM30) and the Advanced Space borne Thermal Emission and Reflection Radiometer Global DEM version 2.0 (ASTER GDEM2) was statistically assessed using high accuracy GPS survey data. Root-Mean-Square errors of ~5.40 m, ~7.47 m and ~20.03 m were obtained for ALOS W3D30, SRTM30 and ASTER GDEM2 respectively. In further analyses, we discovered that ALOS W3D30 and SRTM30 were much more accurate in regions where the height intervals were within 201 m - 400 m and >801 m. ALOS W3D30 proved to be the most accurate DEM that best represents the topography of the earth’s surface and could be used for some earth and environmental applications in Nigeria. We recommend that this study should serve as a guide in the use of any of these DEMs for earth and environmental applications in Nigeria.

纳米Al2O3对CaTiO3-（La,Nd）AlO3陶瓷的烧结温度和介电特性的影响

为了降低Ca Ti O3-（La,Nd）Al O3（简称CT-LNA）陶瓷的烧结温度和提高其介电性能,研究纳米Al2O3对Ca Ti O3-（La,Nd）Al O3陶瓷的烧结温度和介电性能的影响。固相法制备粉料,采用XRD和SEM分析其晶相和显微结构,用网络分析测试样品的介电参数,结果表明,纳米Al2O3可促进陶瓷烧结,在1320~1400℃范围内可烧结成瓷,并具有较好的微波介电性能。当纳米Al2O3含量为50 wt%时,陶瓷在1340℃烧结可获得优良的微波介电性能：介电常数为42.6,Q×f值高达34,000GHz,频率温度系数为＋4.8 ppm/℃。

含AlO_2^-废碱洗液中Al和过量碱含量的测定

为了方便检测Al-Ni合金粉碱洗液中含NaAlO2和NaOH浓度,用EDTA络合铝离子,再用标准氯化锌溶液返滴定测量铝含量,用盐酸滴定NaOH。本方法再现性好,简单方便,满足现场分析配合要求。

Fast and efficient removal of silver(Ⅰ) from aqueous solutions using aloe vera shell ash supported Ni_(0.5)Zn_(0.5)Fe_2O_4 magnetic nanoparticles

Silver (I) was removed from aqueous environment by aloe vera shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles.The adsorbent was characterized by several methods including X-ray diffraction (XRD), scanning electron microscopy (SEM), BETisotherm, vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FT-IR). To determine the absorptionof silver (I) by this adsorbent, different pH values (2?7), adsorbent dose (0.01?0.5 g), concentrations of Ag+ (50, 100, 200, 300, 500,700 and 1000 mg/L) and exposure time (5?100 min) were experimented. The highest removal efficiency of Ag+ was achieved underoptimum condition (30 min and pH=5). The optimum adsorbent dose was 0.20 g (in 50 mL of 100 mg/L Ag+ solution), whichachieved a removal efficiency of 98.3%. The maximum monolayer adsorption capacity based on the Langmuir isotherm is243.90 mg/g. Characterization results revealed that specific surface area and porous volume were 814.23 m2/g and 0.726 cm3/g,respectively. The experimental data were fitted well with the Langmuir and Freundlich isotherm models. Synthesized adsorbent has desired surface area and adsorptive capacity for silver (I) adsorption in aquatic environment.

固溶体红色荧光粉Ca(TiO_3)_(1-x/2)(AlO_2)_x:Eu的制备及性能研究

通过固相法合成含有不同AlO_2-离子浓度的红色荧光粉Ca(TiO_3)_(1-x/2)(AlO_2)_x:Eu。XRD分析表明:当Al O2-离子掺杂浓度低于30%时,Ca(TiO_3)_(1-x/2)(AlO_2)_x:Eu与CaTiO_3具有相似的钙钛矿结构;此外,AlO_2-离子的固溶导致该荧光粉在617nm处的荧光发射强度得到了极大地增强。实验表明:是该荧光粉具有最强荧光发射强度的Al O2-掺杂浓度为20mol%。更重要的是荧光粉Ca(TiO_3)0.89(AlO_2)0.22:Eu不但可以被Ga N基NUV(395~400nm)LED激发,而且还能被Ga N-LED(465nm)有效激发。实验表明:Ca(TiO_3)(Al O):Eu是一种性能优越的制备三基色LED的红色荧光粉。

基于网络药理学及分子对接揭示芦荟大黄素的降糖机制

该文通过网络药理学结合分子对接的技术研究了芦荟大黄素改善Ⅱ型糖尿病的作用机制。利用数据库平台筛选出芦荟大黄素的潜在靶点和改善治疗Ⅱ型糖尿病的相关靶点,将二者取交集获得芦荟大黄素改善Ⅱ型糖尿病的潜在靶点;构建共同靶点间的蛋白互作网络,并对共同靶点进行GO功能注释和KEGG通路富集分析;通过筛选主要通路并构建“芦荟大黄素-Ⅱ型糖尿病-通路”网络图,对芦荟大黄素与通路及各通路所富集的靶点间的联系进行可视化分析,通过分子对接,研究芦荟大黄素与关键靶点的结合机制。结果表明,芦荟大黄素具有63个改善治疗Ⅱ型糖尿病的相关靶点,并根据蛋白互作网络筛选出AKT1、PIK3CA、HRAS和MAPK8等22个核心靶点,这些靶点主要富集在PI3K/AKT和胰岛素抵抗等信号通路,芦荟大黄素主要通过氢键、范德华力和π-π相互作用等分子间作用力与靶点结合,从而调控靶点的表达,改善Ⅱ型糖尿病。

综合InSAR技术和多源SAR数据在滑坡变形监测中的应用——以吉林治新村滑坡为例

为实现对吉林省治新村滑坡的有效监测,文章选取2017年27景Sentinel-1A数据,基于小基线雷达干涉测量技术(SBAS-InSAR)对治新村滑坡进行形变监测,分析了其时序演化态势。选用2016、2017年2景ALOS-2数据,采用差分雷达干涉测量技术(D-InSAR)监测了该滑坡形变体的特征。SBAS-InSAR对滑坡形变时序演化态势进行监测,而D-InSAR则主要对滑坡具体的形变体进行形变监测,且L波段的ALOS-2数据穿透性强于C波段的Sentinel-1A数据,可以获得更完整的干涉信息,两者监测结果可交叉验证,提高结果的可靠性。SBAS-InSAR监测结果表明:治新村滑坡汇水区滑坡后缘在监测期间发生了沉降,并且在2017年7月5—29日期间滑坡后缘地表沉降达12.47 mm,监测期间平均沉降速率为2.88 mm/a;位于山谷的受威胁居民区发生了抬升,至2017年12月8日平均累计抬升达19.59 mm,监测期间平均抬升速率19.99 mm/a。D-InSAR结果显示:治新村滑坡汇水区斜坡存在5处主要变形体,面积最大变形体17973 m^(2),位于西侧斜坡,最不稳定变形体位于斜坡东侧,监测期间平均累计形变量最大达49.9 mm。两种监测方法都表明,滑坡灾害威胁主要来自植被覆盖较差的西侧斜坡,雨季是治新村滑坡灾害防治的重点时期。