Topographic Correction-Based Retrieval of Leaf Area Index in Mountain Areas

Leaf Area Index(LAI)is a key parameter in vegetation analysis and management,especially for mountain areas.The accurate retrieval of LAI based on remote sensing data is very necessary.In a study at the Dayekou forest center in Heihe watershed of Gansu Province,we determined the LAI based on topographic corrections of a SPOT-5.The large variation in the mountain terrain required preprocessing of the SPOT-5 image,except when orthorectification, radiation calibration and atmospheric correction were used.These required acquisition of surface reflectance and several vegetation indexes and linkage to field measured LAI values.Statistical regression models were used to link LAI and vegetation indexes.The quadratic polynomial model between LAI and SAVI (L=0.35)was determined as the optimal model considering the R and R2 value.A second group of LAI data were reserved to validate the retrieval result.The model was applied to create a distribution map of LAI in the area.Comparison with an uncorrected SPOT-5 image showed that topographic correction is necessary for determination of LAI in mountain areas.

A correction method of encoder bias in satellite laser ranging system

In a satellite laser ranging telescope system, well-aligned encoders of the elevation and azimuth axes are essential for tracking objects. However, it is very difficult and time-consuming to correct the bias between the absolute-position indices of the encoders and the astronomical coordinates, especially in the absence of a finder scope for our system. To solve this problem, a method is presented based on the phenomenon that all stars move anti-clockwise around Polaris in the northern hemisphere. Tests of the proposed adjustment procedure in a satellite laser ranging （SLR）system demonstrated the effectiveness and the time saved by using the approach, which greatly facilitates the optimization of a trackin~ svstem.

Numerical simulation-based correction of relative permeability hysteresis in water-invaded underground gas storage during multi-cycle injection and production

By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores,we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle injection and production.A correction method for relative permeability hysteresis in numerical simulation of water-invaded gas storage has been worked out using the Carlson and Killough models.A geologic model of water-invaded sandstone gas storage with medium-low permeability is built to investigate the impacts of relative permeability hysteresis on fluid distribution and production performance during multi-cycle injection and production of the gas storage.The study shows that relative permeability hysteresis effect occurs during high-speed injection and production in gas storage converted from water-invaded gas reservoir,and leads to increase of gas-water transition zone width and thickness,shrinkage of the area of high-efficiency gas storage,and decrease of the peak value variation of pore volume containing gas,and then reduces the storage capacity,working gas volume,and high-efficiency operation span of the gas storage.Numerical simulations exhibit large prediction errors of performance indexes if this hysteresis effect is not considered.Killough and Carlson methods can be used to correct the relative permeability hysteresis effect in water-invaded underground gas storage to improve the prediction accuracy.The Killough method has better adaptability to the example model.

Estimating vertical vegetation density through a SPOT5 imagery at multiple radiometric correction levels

There is growing concern about remote sensing of vertical vegetation density in rapidly expanding peri-urban interfaces. A widely used parameter for such density, i.e., leaf area index （LAI）, was measured in situ in Nanjing, China and then correlated with two vegetation indices （VI） derived from multiple radiometric correction levels of a SPOT5 imagery. The VIs were a normal- ized difference vegetation index （NDVI） and a ratio vegetation index （RVI）, while the four radiometric correction levels were i） post atmospheric correction reflectance （PAC）, ii） top of atmosphere reflectance （TOA）, iii） satellite radiance （SR） and iv） digital number （DN）. A total of 157 LAI-VI relationship models were established. The results showed that LA! is positively correlated with VI （r varies from 0.303 to 0.927, p 〈 0.001）. The R： values of＂pure＂ vegetation were generally higher than those of mixed vegetation. The average R2 values of about 40 models based on DN data （0.688） were higher than that of the routinely used PAC （0.648）. Independent variables of the optimal models for different vegetation quadrats included two vegetation indices at three radiometric correction lev- els, indicating the potential of vegetation indices at multiple radiometric correction levels in LAI inversion. The study demonstrates that taking heterogeneities of vegetation structures and uncertainties of radiometric corrections into account may help full mining of valuable information from remote sensing images, thus improving accuracies of LAI estimation.

Correcting Image Distortion for Adaptive Cruise Control

One of the main drivers for intelligent transportation systems is safety. Adaptive cruise control, as a common solution for traffic safety, lias extended from radars to cameras. Due to high mobility of vehicles and unevenness of roads, the picture quality of cameras has been great challenges for camera-based adaptive cruise control. In this paper, an image distortion correction algorithm is addressed. Our method is based on optical flow technology which is normally applied in motion estimation and video compression research. We are the first to attempt to adapt it in image distortion correction. Two optical flow approaches, the Lucas-Kanade method and the Horn-Schunck method, are selected and compared. The procedure of image distortion correction using the optical flow method has been tested by both synthetic test images and camera images. The experimental results show that the Lucas-Kanade method is more suitable in the correction of image distortion.

Isotropic Double Index for Quantum Errors in One Qubit

This article describes a proposal for a double index to estimate the isotropic components of unitary errors in a quantum computation circuit. In the context of this work the error is considered isotropic if it has spherical symmetry about the state of interest. The theoretical definition is given, as well the numerical approximation for practical purposes. The index is tested in some simple examples and the geometric distortion of the propagated error is studied for an inaccurate Shor 9-qubits correcting code.

Test and Correction of CUACE Model in Air Quality Forecast in the Qinghai-Tibet Plateau:A Case Study of Xining City

Based on the data of national monitoring points of air pollution control in Xining from 2015 to 2017,the air quality prediction of CUACE model in Xining was tested by using the method of national environmental meteorological numerical model prediction quality inspection and evaluation.The results show that the prediction accuracy of the CAUCE model for the primary pollutants in Xining region during 2015-2017 was generally higher in the winter half year,and the maximum appeared in November 2016.The prediction accuracy in 24,48 and 72 h was more than 70%.The prediction accuracy of the model in the summer half year was low.The primary pollutants in Xining area were PM_(10),PM_(2.5),O_(3),NO_(2) and CO.The prediction accuracy of PM_(10) was the highest,followed by PM_(2.5),while that of O 3 was the lowest.TS score of 24-hour forecast of light pollution was greater than 0 in the winter half year,and it was the highest in December when the unreported rate was also the highest;the empty report rate existed all year round,and was the highest from May to June.Forecast deviation was greater than 0 in the winter half year,and the maximum appeared in January.The 48-hour and 72-hour model forecast were consistent with the 24-hour forecast.The forecast effect of the model on sudden pollution weather was poor,and moderate pollution,severe pollution,and serious pollution weather occurred less frequently in Xining region,so there was fewer model forecast of this kind of pollution.Besides,among the 24-,48-and 72-hour forecast values of the model,there were many empty reports of this kind of pollution,and the empty report rate was high.

Influences of laparoscopic radical correction of oophoroma combined with chemotherapy on tumor related factors and immunologic function levels

Objective: To study the influence of laparoscopic radical correction of oophoroma combined with chemotherapy on Tumor related factors and immunologic function levels. Methods:Retrospective analyses the 95 cases of ovarian cancer in our hospital from January 2013 to September 2017, which were divided into the control group and the observation group. The patients in the observation group underwent laparoscopic ovarian cancer radical surgery, the control group underwent open radical resection of ovarian cancer, two patients were combined with TP chemotherapy, the levels of serum MMP-9, HE4, YKL-40, EPO, PRL, TSGF and T lymphocyte subsets (CD3+, CD4+, CD8+ and CD4+/CD8+) in two groups before and after treatment were detected and compared. Results: (1) Before treatment, there was no statistical difference between the levels of serum MMP-9, HE4, YKL-40, EPO, PRL, TSGF in the two groups;After treatment, the levels of serum MMP-9, HE4, YKL-40, EPO, PRL, TSGF in the control group were statistically significant compared with those before treatment in the same group, and the differences were statistically significant between the two groups. (2) Before treatment, there was no statistical difference between the levels of serum T lymphocyte subsets (CD3+, CD4+, CD8+, CD4+/CD8+) in the two groups;After treatment, the differences of serum CD3+, CD4+, CD8+, CD4+/CD8+ were statistically significant compared with those before treatment in the same group, but the differences were not statistically significant between the two groups. Conclusion: Chemotherapy in patients with ovarian cancer TP in laparoscopic radical resection after, can not only significantly improve the patient's serum MMP-9, HE4, YKL-40, EPO, PRL, TSGF level. Moreover, compared with the simple operation, this method does not significantly affect the T lymphocyte subsets of the patients, and is worthy of clinical application.

Use of sampling based correction for non-radioactivity X-ray energy calibration

As the requirement of non-radioactivity measurement has increased in recent years,various energy cali- bration methods applied in portable X-ray fluorescence (XRF) spectrometers have been developed. In this paper,a sampling based correction energy calibration has been discussed. In this method both history information and current state of the instrument are considered and relative high precision and reliability can be obtained.

基于定位校正指数的嘧啶类含能材料爆轰性能

为研究嘧啶类含能化合物的爆轰性能与其分子结构的构效关系,根据嘧啶类含能化合物分子中原子相互连接的空间特性,提出了一种新的分子结构指数——定位校正指数B;此外还计算了19个含能化合物分子的电拓扑态指数,并优化筛选出其中的E 13作为分子结构描述符,将E 13与定位校正指数B结合,与嘧啶类含能化合物的爆轰性能进行回归分析;将B和E 13这两种结构指数作为BP神经网络的输入变量,神经网络结构采用2-3-1的结构方式,构建了预测嘧啶类含能化合物爆轰性能好的神经网络法模型。结果表明,每个模型的总相关系数均超过0.99,达优级相关,计算得到的氧平衡、爆热、爆速和爆压的预测值与文献值的平均相对误差分别为1.59%、1.05%、0.37%和1.28%;如将指数扩展到与噁三唑稠环类含能材料分子、含氟唑类含能化合物分子的爆轰性能等进行分析预测,同样能得到令人满意的结果。说明嘧啶类含能材料分子的爆轰性能与定位校正指数、电拓扑态指数有良好的非线性关系。

老年髋部骨折术后1年病死率的危险因素分析及年龄矫正查尔森合并指数对其的预测价值

目的分析影响老年髋部骨折患者手术后1年病死率的危险因素及年龄矫正查尔森合并指数对其的预测价值。方法回顾性分析2018年1月至2022年11月在北京市顺义区医院创伤骨科行髋部骨折手术治疗的老年患者的病历资料,符合纳入标准共652例,收集年龄、性别、骨折侧别、骨折类型、美国麻醉医师协会(ASA)分级、住院天数、麻醉方式、术后白蛋白、术后白细胞、术后血红蛋白、年龄矫正查尔森合并指数(ACCI)和是否发生肺炎等信息,分析与患者1年病死率相关的危险因素。结果652例患者术后1年的病死率为21.5%(140/652)。单因素Cox回归分析显示年龄、住院时间、ACCI及术后是否发生肺炎与术后1年病死率有统计学意义。多因素Cox回归分析显示年龄(HR=1.087,95%CI:1.060~1.114,P=0),ACCI(HR=1.645,95%CI:1.548~1.747,P=0),术后发生肺炎(HR=2.353,95%CI:1.624~3.408,P=0)是老年髋部骨折患者1年内死亡的危险因素。ACCI预测老年髋部骨折患者术后1年病死率的AUC为0.912,最佳阈值为5.5时的特异度为0.834,敏感度为0.871。结论年龄、ACCI、术后发生肺炎时老年髋部骨折术后1年死亡的独立危险因素,ACCI对预测老年髋部骨折术后1年病死率有一定价值,可为临床病情评估提供方法。

基于指标修正的AHP-FCEM法长输油气管道风险评价

针对国内在用长输油气管道使用管理过程中存在的高风险、事故多发、风险不可控的现状,在多方位调研的基础上,提出一种综合了层次分析法(AHP)、区间估计分析理论和模糊综合评价法(FCEM)的评价方法。利用层次分析法的优势建立初步评价体系,接着采用区间估计分析理论对“弱权重指标”进行筛选,优化形成包含5个Ⅰ级指标和25个Ⅱ级指标的最终评价体系,最后应用模糊评价法通过两级运算确定评价目标的模糊隶属度,进而得到管道的风险等级。实例验证表明,该评价方法的结果与实际情况相吻合,可为长输油气管道的科学化管理提供技术支撑。

一测多评法测定法制半夏曲中11种成分含量及其GRA、EW-TOPSIS质量评价

目的采用一测多评(QAMS)法同时测定法制半夏曲中肌苷、鸟苷、腺苷等11种成分含量,并建立其灰色关联度分析(GRA)联合熵权逼近理想解排序分析法(EW-TOPSIS)综合质量评价方法。方法采用Shimadzu C 18色谱柱;乙腈-0.5%醋酸为流动相,梯度洗脱,流速1.0 mL·min-1;检测波长254和290 nm。以对甲氧基肉桂酸乙酯为内参比物质,计算其他10个成分的相对校正因子(RCF),测定各成分含量。采用GRA联合EW-TOPSIS模型对法制半夏曲进行综合质量评价。结果法制半夏曲中11种成分在一定浓度范围内线性关系良好,相关系数均>0.999;平均加样回收率96.94%~100.12%(RSD<2.0%,n=9);QAMS与外标法(ESM)实测值无明显差异。GRA模型相对关联度0.2903~0.6187,EW-TOPSIS模型相对接近度0.2114~0.6343;GRA和EW-TOPSIS模型综合评价结果基本一致。结论QAMS法便捷、准确,可用于法制半夏曲多指标成分定量控制,GRA联合EW-TOPSIS模型可用于法制半夏曲综合质量评价。

福州都市圈生态系统服务价值时空演变及生态-经济协调发展

量化分析区域生态系统服务价值(ESV)演变以及空间分异因素,研究生态-经济协调一致性发展特征,有助于推动城市群与都市圈生态功能提升。以福州都市圈为例,基于2001年、2010年、2020年遥感影像数据,采用优化生态系统服务价值评估模型、重心模型、变异系数、协调性指数和一致性指数,结合GIS空间可视化分析,测度福州都市圈生态系统服务价值演变并分析其与经济发展的时空协调演变特征,最后对福州都市圈的生态-经济协调发展战略提出建议。结果表明:①2001~2020年,福州都市圈整体生态系统服务价值先减后增;其中,福州、莆田先减后增,宁德四县(市、区)和南平三区(市)则持续增加;②第一产业占比、年平均气温和植被覆盖率对生态系统服务价值的空间分异解释力较高,在原有自然条件的限制下,福州都市圈生态系统服务价值的空间分异更易受人为因子的干扰而扩大;③福州、莆田、宁德四县(市、区)的生态系统服务重心具有不断远离经济重心的趋势,二者逐渐割裂;④福州都市圈生态经济协调发展冲突尚不明显,但生态系统服务价值增长速度落后于GDP增长速度的区域数量较多,经济发展正在承受越来越大的生态压力,2001~2020年间福州都市圈形成福州、莆田、宁德城区经济集聚与中部六县生态集聚并存的格局。

降水产品偏差校正方法在长江子流域应用效果

降水产品的精度受到多种因素的影响,相对于地面站点观测降水表现出不同程度的偏差,需在实际应用前进行偏差校正并评估其适用性。为探寻适用于不同降水产品在长江流域不同区域内的偏差校正方法,评估CMFD、MSWEP和ERA5-Land这3种降水产品在长江流域内3个气候、地形和面积有较大差异的子流域内的适用性,并在此基础上对比使用3类7种方法对日尺度降水值进行偏差校正。结果表明:校正后的降水产品的适用性得到了不同程度的提升,而局部强度缩放与三伽玛分布结合校正法在3种降水产品和3个子流域的校正效果均为最优。校正方法的校正幅度与降水产品在研究区域的适用性存在反相关关系,产品的适用性越差,精度评价指标的改进幅度越明显。研究结果可为后期不同降水产品在长江流域不同子流域的准确应用提供可参考的校正方法。

考虑环境温度效应的隔震橡胶支座力学性能试验

为研究环境温度对隔震橡胶支座力学特性的影响,利用高速压剪试验设备针对直径700 mm的隔震橡胶支座(LRB700以及LNR700)开展一系列不同温度(-20、0、23℃)、不同频率(0.2、0.25、0.3 Hz)以及不同剪应变(50%、100%、250%)的压剪试验。鉴于高速高压(15 MPa的竖向压应力)试验设备本身会产生较大的惯性力以及摩擦力,分别提供相应的修正方案以便准确获得支座的力学性能指标。结果表明:随着加载圈数的增加,LRB700内部铅芯的温度变化较为明显,并呈现关于高度的对称性,而LNR700内壁温度变化很小;LRB700及LNR700的相关力学性能指标(如水平屈服剪力、屈服后水平刚度以及水平等效刚度)随环境温度的降低都表现出不同程度的上升趋势,其中,LRB700水平屈服剪力上升15%~32%,LRB700屈服后水平刚度上升7%~16%,LRB700与LNR700水平等效刚度分别上升12%~23%、5%~16%。基于上述结果并结合相关规范针对LRB700以及LNR700提出考虑环境温度效应的力学性能调整系数。

线性学术评价中权重扭曲危害、成因及对策研究——最小均值指标权重修正法

[目的/意义]在线性学术评价中,普遍存在初始权重与实际权重不一致问题。[方法/过程]文章以学术期刊评价为例,在对其产生机制进行理论分析的基础上,研究了其危害,并对现有的几种解决方法的不足进行了剖析,提出一种新的最小均值指标权重修正法,并进行了实证检验。[结果/结论]研究结果表明:最小均值指标权重修正法可以彻底解决自然权重问题;要重视自然权重问题对学术评价科学带来的影响;最小均值指标权重修正法也适用于所有的线性评价。

混凝土重力坝变形监测数据的相关性分析

混凝土重力坝的变形量可直观反映大坝的综合运行性态,而变形监测数据是坝体变形的直接体现。因此,从时间和空间上掌握坝体变形监测数据之间的规律与相关性,对于大坝后续的异常检测及安全评价等研究具有重要意义。结合大坝变形监测数据实例,分析了环境因素对位移影响存在的滞后性,利用时空相似指数对大坝不同测点间位移构建了综合相似度指标,运用皮尔逊相关系数、斯皮尔曼等级相关系数和最大信息系数法分析了环境因素与测点位移的相关性以及各测点之间变形位移的相关性,为后续建立健康服役诊断模型等更深层次的研究奠定了坚实的基础。

不同矫治技术在口腔正畸治疗中对患者牙周指数及美观度的影响比较

目的:探讨传统固定及无托槽隐形矫治技术对口腔正畸牙周指数及患者美观度的影响。方法:选取2019年4月-2021年4月于笔者医院行正畸治疗的106例患者作为研究对象,依据治疗方式不同分为观察组(n=51)与对照组(n=55)。两组患者入院后均行口腔卫生宣教,并指导患者学习改良Bass刷牙法,患者治疗期间均使用相同的牙膏及牙刷,对照组患者以传统固定矫治技术治疗,观察组患者以无托槽隐形矫治技术治疗。对比两组患者正畸治疗时间、倾斜牙扶正时间及扭转牙转正时间;对比两组患者治疗前后牙龈指数(Gingival index,GI)、菌斑指数(Plaque index,PLI)、龈沟探诊深度(Sulcus probing depth,SPD)、龈沟出血指数(Sulcus bleeding index,SBI)及龈沟液内肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)、白细胞介素-1β(Interleukin-1β,IL-1β),评估两组患者治疗后满意度。结果:观察组正畸治疗时间、倾斜牙扶正时间、扭转牙转正时间显著短于对照组(P<0.05)。两组治疗后GI、PLI、SBI水平显著高于治疗前(P<0.05),且观察组GI、PLI、SBI水平显著低于对照组(P<0.05)。两组治疗后龈沟液TNF-α、IL-β水平显著低于治疗前(P<0.05),且观察组龈沟液TNF-α、IL-β水平显著低于对照组(P<0.05)。观察组治疗后美观程度评分显著高于对照组(P<0.05)。结论:相对于传统固定矫治技术,无托槽隐形矫治技术应用于正畸治疗中可缩短正畸治疗时间,且矫治器对正畸患者的牙周健康影响轻微,具有较好的美观度,患者满意度高。

基于TLE数据的大气密度反演与校正

用于航天器轨道预报的热层密度模型普遍存在30%左右的误差,影响LEO卫星的精密轨道确定和载荷控制。基于低轨航天器平运动变化与大气密度的关系,使用GRACE(gravity recovery and climate experiment)卫星TLE数据反演2003、2007年沿轨大气密度,通过比较反演值、模型值和实测值的关系分析误差产生原因,使用对数正态分布拟合密度比值。通过分析太阳辐射、地磁指数对大气密度变化的影响,提出一种基于空间环境指数的热层大气密度模型校正与预报方式。使用该方法对2003、2004、2007、2008年的MSIS86模型计算密度进行修正,将模型平均相对误差从33.33%~59.62%降低到11.55%~15.13%,太阳活动低年改进量是高年的1.5~2倍。对2009年经验模型结果进行预报校正,将预报误差降低36.49%,提高了模型精度。