基于Pearson相关系数与广义S变换的低压直流微电网的故障选线方法

针对低压直流微电网线路的故障选线方法的研究有限,提出一种基于Pearson相关系数与广义S变换的故障选线方法。首先,介绍了低压直流微电网的一般组成。在此基础上,研究了低压直流微电网的单极故障以及极间故障的故障特征,提出选线方法,对各线路正负极首末端电流差进行Pearson相关系数计算来确定故障线路。然后对所选故障线路正负线路首端的电流量进行广义S变换,计算出其能量和的比值判别故障极性或者极间故障。最后,在PSCAD/EMTDC中搭建出低压直流微电网模型以输出各线路电流数据,并利用Matlab对数据进行仿真。结果表明,所提选线方法直接有效,且耐受过渡电阻的能力较强。

基于CD-BSMOTE的D-S证据融合变压器故障诊断

针对变压器油中溶解气体数据集不均衡特性对故障诊断结果的影响,提出一种基于清除临界点改进的边界合成少数类过采样算法均衡数据集和Pearson冲突距离改进D-S证据融合的变压器故障诊断模型。首先,对少数类样本进行均衡化处理,根据K-means聚类结果清除处于临界位置的样本;其次,搭建梯度提升树、随机森林、BP神经网络的故障诊断模型,实现变压器故障初步诊断;接着引入Pearson冲突距离改进D-S证据融合模型,实现诊断结果的融合决策;最后,经实际算例分析,诊断精确率达到92.65%。结果表明,所建模型能有效解决数据不平衡对诊断结果的影响,提高故障诊断精度。

Correction to:High‑Index‑Faceted Ni3S2 Branch Arrays as Bifunctional Electrocatalysts for Efficient Water Splitting

In the original publication,Figure S4 is an ancillary image to compare the specific surface areas of TiO2/Ni3S2 and Ni3S2 samples and it was incorrectly published.To better serve our readers,the correct figure is provided in this correction.The BET values are correct and unaffected.The corresponding figure caption,data analysis and conclusions are not affected and thus not to be changed.The authors would like to apologize for any inconvenience caused.

Spatio-temporal Variation Characteristics of Extreme Climate Events and Their Teleconnections to Large-scale Ocean-atmospheric Circulation Patterns in Huaihe River Basin,China During 1959–2019

Huaihe River Basin(HRB) is located in China’s north-south climatic transition zone,which is very sensitive to global climate change.Based on the daily maximum temperature,minimum temperature,and precipitation data of 40 meteorological stations and nine monthly large-scale ocean-atmospheric circulation indices data during 1959–2019,we present an assessment of the spatial and temporal variations of extreme temperature and precipitation events in the HRB using nine extreme climate indices,and analyze the teleconnection relationship between extreme climate indices and large-scale ocean-atmospheric circulation indices.The results show that warm extreme indices show a significant(P < 0.05) increasing trend,while cold extreme indices(except for cold spell duration) and diurnal temperature range(DTR) show a significant decreasing trend.Furthermore,all extreme temperature indices show significant mutations during 1959-2019.Spatially,a stronger warming trend occurs in eastern HRB than western HRB,while maximum 5-d precipitation(Rx5day) and rainstorm days(R25) show an increasing trend in the southern,central,and northwestern regions of HRB.Arctic oscillation(AO),Atlantic multidecadal oscillation(AMO),and East Atlantic/Western Russia(EA/WR) have a stronger correlation with extreme climate indices compared to other circulation indices.AO and AMO(EA/WR) exhibit a significant(P < 0.05) negative(positive)correlation with frost days and diurnal temperature range.Extreme warm events are strongly correlated with the variability of AMO and EA/WR in most parts of HRB,while extreme cold events are closely related to the variability of AO and AMO in eastern HRB.In contrast,AMO,AO,and EA/WR show limited impacts on extreme precipitation events in most parts of HRB.

Correction to:Remotely Activated Nanoparticles for Anticancer Therapy

Correction to:Nano-Micro Lett.(2021)13:11 https://doi.org/10.1007/s40820-020-00537-8 In the original publication figures 7 and 11 need to be updated with correct values.The correct version of Figs.7 and 11 is provided in this correction.The original article has been corrected.

Author’s Correction

We have made a clerical error in Table 1 on the page of 239, Volume 23, No.4 of Journal of Medical Colleges of PLA (the article is entitled as Expression and role of AQP1 in cervical squamous carcinoma

An Improved 6S Code for Atmospheric Correction Based on Water Vapor Content

Water vapor content in the atmosphere is very significant for atmospheric correction of optical remote sensing data. Nowadays, the common atmospheric correction models use a single value of the average water vapor content of the study area to perform atmospheric correction. As the distribution of water vapor content varies greatly with time and space, it is obviously inaccurate to represent the total water vapor conditions of the whole area by just reading the average water vapor content. In this study, we altered the 6S sources so that it could read the water vapor content image which was retrieved from MODIS 1 km data. Atmospheric correction was implemented for the band 1 of MODIS 500 m data pixel-by-pixel using the improved 6S model. In comparison with the traditional 6S model, this improved 6S model is more reasonable in atmospheric correction, for it considers the spatial distribution of the water vapor content retrieved from MODIS data in the near infrared to define the atmospheric conditions for simulating the atmospheric radiative transfer. The results corrected by the improved 6S model showed more reasonable in pixel spatial distribution and closer histogram with the original image than those by traditional 6S model.

Clinical study of correction of finger flexion deformity in Dupuytren's disease

Objective To explore surgical technique and its result in correcting finger contracture in Dupuytren’s disease. Methods Seventeen cases of Dupuytren’s disease with 58 years mean age were studied in this group ( 15 males and 2 females) . Among them,8 sides were with flexion eontracture of little finger,8 sides with flexion contracture of little and ring fingers,1 side with

Pearson、Spearman与Kendall's Tau相关分析的Excel实现

目的探讨用Excel实现Pearson、Spearman与Kendall’s Tau相关分析的方法。方法利用Excel中的单元格能调用其它单元格内数据的特点,将相关系数及其假设检验的计算公式分为多个中间结果,合理布置在工作表的各单元格中,最终可得到公式的计算结果,并根据结果作出统计分析与判断。结果建立"两变量相关频数数据"和"两变量相关原始数据"的两个Excel工作表后,进行数据进行Pearson、Spearman与Kendall’s Tau相关分析时仅仅录入频数数据(或原始数据)和显著性水准α,不须再录入任何统计公式和命令,就能立即得到统计结论。结论利用Excel能直观快速地进行数据的Pearson、Spearman与Kendall’s Tau相关分析。

Analysis of S^p_q current systems by using corrected geomagnetic coordinate

The S^p_q equivalent current system of the quiet day geomagnetic variation in the polar region is very complicated. It is composed of several currents, such as the ionospheric dynamo current and the auroral electrojet caused by the field aligned current. S p q is unsymmetrical in both polar regions. In this paper, the S p q current systems are analyzed in the corrected geomagnetic coordinates (CGM) instead of the conventional geomagnetic coordinates (GM), and the symmetries of the S p q current in different systems are compared. Then the causes of S p q asymmetry in the GM coordinates are discussed; the effects of each component in S p q are determined.

Multiplet relative location approach and waveform correlation correction and their application

The theory and method of relative location technique were described in the paper. The travel-time difference equa-tions for five phases (Pg, Sg, P11, S11 and Pn) were given. By using the multiplet relative location approach and wave correlation correction, the aftershock cluster of the Shunyi earthquake occurred on December 16, 1996 was relocated. The depth calculation was constrained by using multiple seismic phases. The relocation results were compared with that from traditional absolute location techniques.

Corrected Transposition of the Great Arteries with Ebstein’s Anomaly, Dysplasia of the Mitral Leaflets and Persistence of Left Superior Vena Cava in an Adult

Introduction: Congenitally corrected transposition of the great arteries (cc-TGA) is a congenital heart disease rarely described among adult population, especially if it is associated with other abnormalities such as Ebstein’s anomaly and abnormal origin of coronary arteries. Case presentation: Twenty-two-year-old woman admitted to intensive care unit with acute decompensated heart failure. The transthoracic echocardiography demonstrated atrioventricular and ventriculoarterial discordance. The left-sided atrioventricular valve, in this case, the tricuspid valve, showed apical displacement of the septal valve suggesting Ebstein’s anomaly. The computed tomography corroborated these findings and additionally showed a left superior vena cava and an abnormal origin of the coronary arteries. The patient is in NYHA functional class II, receiving treatment with diuretic, digitalis, beta-blockers and angiotensin-converting enzyme (ACE) inhibitor. Conclusion: This is a very interesting case of an adult in the third decade of life with cc-TGA associated with abnormalities not described in the literature that had reached adulthood. Noninvasive images play an important role in its diagnosis.

基于数据特征提取和SSA-BiLSTM的短期风电功率预测

为提高风电功率预测的准确性,提出了一种基于数据特征提取和麻雀算法优化双向长短期记忆网络(sparrow search algorithm optimised bi-directional long and short-term memory network,SSA-BiLSTM)短期风电功率预测模型。首先根据皮尔逊相关系数(Pearson correlation coefficient,PCC)分析风电数据中各影响因素与风电功率之间的相关性,根据计算结果将功率无关的因素去除。然后,采用自适应噪声完全集成经验模态分解(complete ensemble empirical mode decomposition with adaptive noise,CEEMDAN)将原始风电功率序列进行分解,得到一系列子序列分量。再将所有子序列输入麻雀算法(sparrow search algorithm,SSA)优化的双向长短期记忆(bi-directional long short-term memory,BiLSTM)模型中进行预测,根据所得预测值对风速序列进行修正。将修正所得的风速序列与风电功率序列作为输入,送入SSA-BiLSTM模型中进行预测。最后,由实验结果分析并对比得出,该模型具有更好的风电功率预测精度。

Natural variations and geographical distributions of seed carotenoids and chlorophylls in 1167 Chinese soybean accessions

Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.Genotype,planting year,accession type,seed cotyledon color,and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.The mean total carotenoid content was in the range of 8.15–14.72μg g–1 across the ecoregions.The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.Remarkably,lutein was the most abundant carotenoid in all the germplasms,ranging from 1.35–37.44μg g–1.Carotenoids and chlorophylls showed significant correlations with other quality traits,which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.Collectively,our results demonstrate that carotenoids are adequately accumulated in soybean seeds,however,they are strongly influenced by genetic factors,accession type,and germplasm origin.We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs,and thereby as the raw materials for food sectors,pharmaceuticals,and the cosmetic industry.

The Effects of Learner’s Individual Differences on the Written Corrective Feedback

From the perspective of individual learner differences,this paper aims to show the readers an outline of the influence of individual learner differences on written corrective feedback.Based on 200 eighth and ninth grade junior high school students’thinking patterns and tests,60 students were selected as subjects in this study.Based on the comparative analysis and error analysis in second language acquisition as the main theoretical basis,this study analyzed the common types of errors in the use of nonpredicate verbs in junior high school students and their causes.There are three main questions in this study:how about the error frequency of the five forms(present participle,past participle,infinitive,gerund and independent nominative structure)in the nonpredicate verb learning of junior high school students?What kind of mistakes do junior high school students make in the process of learning non-predicate verbs?According to the conclusion of the investigation and research,the author puts forward some suggestions from the aspects of teachers and students in the last part of the article.

应用6S模式对EOS-MODIS可见光到中红外波段的大气订正

应用 6S辐射传输模式对MODIS可见光到中红外波段的反射率进行大气订正 ,订正过程分两步进行 :首先设定地表为朗伯体 ,再应用二向反射模型BRDF进行订正 ,订正结果与美国MODIS研究组应用MAS实验结果进行比较表明 ,两者变化趋势是一致的 ;经过臭氧、水汽、气溶胶等散射吸收订正 ,对于一定范围的反射率 ,大气订正使植被区红光波段反射率ρ1 降低、近红外波段反射率 ρ2 增加 ,蓝光波段反射率 ρ3降低 ;大气订正后 ,归一化植被指数INDV较大气订正前有所增加 ,增加的最大值为 0 .1 0 4 ,抗土壤 大气植被指数IEV值略有减小 ,减小的最大值为 0 .0 0

用SVGA1薄膜晶体管液晶显示器矫正人眼波像差

在研究了SVGA1薄膜晶体管液晶显示器(TFTLCD)的位相调制特性的基础上,用它作为眼波像差的矫正器件,在用哈特曼夏克波前传感器的眼像差测量系统中对眼波像差进行了成功的矫正.对于5.2mm的瞳孔,矫正后人眼波像差的PV值降低了3倍多,并接近瑞利判据的像差容限.对系统的光学传递函数(MTF)的分析说明,经波像差矫正后眼的空间分辨率由17c/deg提高到38c/deg.

川西地区壳幔结构与汶川M_s8.0级地震的孕震背景

收集了四川数字地震台网记录的57个远震事件,并从宽频带数字化三分量地震记录中计算出了马尔康(MEK)、都江堰(YZP)、GP江(JJS)、江油(ZJG)、广元(YTS)、康定(GDS)、汉源(XJP)、雅安(MDS)、峨眉山(EMS)、沐川(WMP)、仁寿(YGD)、荣县(HMS)等12个台站下方的远震P波径向接收函数.另外,引入地震勘探中的动校正技术,将各台的接收函数校正到67°的参考震中距处,然后对接收函数进行叠加以增强信号,并把叠加接收函数作为台站下方的平均接收函数.最后,利用台站下的平均接收函数反演得到S波速度结构.反演结果表明:以锦屏山—龙门山断裂为界,其西侧地壳厚达70 km,而东侧仅为50 km左右Moho面在断裂下方形成了一个陡坎;川西地区的地壳速度结构与川中地区差异较大,主要表现在川西地区的中地壳存在厚度为8-22 km的低速层.在都江堰、雅安一带,低速层的厚度最大,其厚度在20-22 km之间,其上地壳为一个坚硬固体,在区域构造应力场作用下,形成了孕育大地震的构造环境.

一测多评法同时测定板蓝根中4种核苷及(R,S)-告依春

目的建立同时测定板蓝根中4种核苷(腺苷、胞苷、尿苷、鸟苷)及(R,S)-告依春的HPLC-DAD定量检测方法。方法板蓝根水提取,采用Agilent 1260、Agilent 1100、Waters 2695-2996高效液相色谱仪,流动相为水-甲醇,梯度洗脱。以腺苷、胞苷和尿苷为参照成分计算色谱峰之间的相对校正因子,再与外标法比较。结果 33批板蓝根药材中5种成分相对校正因子在3种仪器检测的耐用性良好。计算值与实测值(外标法)相对误差<5%。结论本研究建立了准确、快速且耐用性良好的板蓝根中5种活性成分同时测定的"一测多评"方法,但本方法得到的相对校正因子受检测波长变化影响较大,5种活性成分同时测定的波长宜为254 nm。

Etvs效应改正中航速、航向角计算方法研究

Etvs效应是影响海洋重力测量精度的主要误差之一,为了减小由定位误差所引起的Etvs效应改正误差,本文基于对常用的直接差分算法进行分析,提出了测线滑动拟合算法。理论研究和实例计算结果表明以测线滑动拟合算法求定航速、航向角比通常采用的直接差分算法使Etvs效应改正精度明显提高。