Comparison study on measurement of rail weld joint between inertial reference method and multi-point chord reference method

Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this field.Design/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength range.Findings – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the track.Originality/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method.

Combination of terrestrial reference frames based on space geodetic techniques in SHAO:methodology and main issues

Based on years of input from the four geodetic techniques （SLR, GPS, VLBI and DORIS）, the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material realization of the ITRS defined in IERS Conventions. The main input includes the time series of weekly solutions （or fortnightly for SLR 1983-1993） of observational data for satellite techniques and session-wise normal equations for VLBI. The set of estimated unknowns includes 3- dimensional Cartesian coordinates at the reference epoch 2005.0 of the stations distributed globally and their rates as well as the time series of consistent Earth Orientation Parameters （EOPs） at the same epochs as the input. Besides the final solution, namely SOL-2, generated by using all the inputs before 2015.0 obtained from short-term observation processing, another reference solution, namely SOL- 1, was also computed by using the input before 2009.0 based on the same combination of procedures for the purpose of comparison with ITRF2008 and DTRF2008 and for evaluating the effect of the latest six more years of data on the combined results. The estimated accuracy of the x-component and y-component of the SOL- 1 TRF-origin was better than 0.1 mm at epoch 2005.0 and better than 0.3 mm yr- 1 in time evolution, either compared with ITRF2008 or DTRF2008. However, the z-component of the translation parameters from SOL-1 to ITRF2008 and DTRF2008 were 3.4 mm and -1.0 ram, respectively. It seems that the z-component of the SOL-1 TRF-origin was much closer to the one in DTRF2008 than the one in ITRF2008. The translation parameters from SOL-2 to ITRF2014 were 2.2, -1.8 and 0.9 mm in the x-, y- and z-components respectively with rates smaller than 0.4 mmyr-1. Similarly, the scale factor transformed from SOL-1 to DTRF2008 was much smaller than that to ITRF2008. The scale parameter from SOL-2 to ITRF2014 was -0.31 ppb with a rate lower than 0.01 ppb yr-1. The external precision （WRMS） compared with IERS EOP 08 C04 of the combined EOP series was smaller than 0.06 mas for the polar motions, smaller than 0.01 ms for the UT1-UTC and smaller than 0.02 ms for the LODs. The precision of the EOPs in SOL-2 was slightly higher than that of SOL-1.

Fiber Bragg Grating Sensor Array System Based on Digital Phase Generated Carrier Demodulation and Reference Compensation Method

A novel fiber Bragg grating （FBG） sensor array system based on digital phase generated carrier （PGC） demodulation and reference compensation method is proposed and set up. Experimental results confirm that the digital PGC demodulation can be used for wavelength-division-multiplexed FBG sensor array and the reference compensation method can reduce the environmental interference by approximately 40 dB in the frequency range from 20 Hz to 2 kHz. The minimum detectable wavelength-shift of the sensor system is 1 × 10^-3 pm/Hz^1/2.

Comparison of Methods for Estimating Reference Crop Evapotranspiration in Beijing

Based on the meteorological data from 1951 to 2015 in Beijing,the reference crop evapotranspiration(ET_0)in Beijing was estimated using the FAO 56 Penman-Monteith method,the FAO PPP-17 Penman method,the Hargreaves method,and the Priestley-Taylor method.The results showed that the monthly and annual changing trends of ET0 estimated by the four methods are basically the same.In general,the ET0 values estimated by the Hargreaves method are the closest to those of the standard method FAO 56 Penman-Monteith,while the difference between the FAO PPP-17 Penman method and the standard method is the biggest.The Hargreaves method is the most suitable method for the estimation of ET0 in Beijing.

Comparison of Calculation Methods for Potential Reference Crop Evapotranspiration ET_0 in North Xinjiang

Reference crop evapotranspiration (ET_0) is a critical part in water cycle and water balance of ecosystem, which is greatly important to effective utilization of agricultural water resources and for making reasonable irrigation system. In order to propose a suitable method for computing ET_0 in North Xinjiang, based on daily meteorological data from May 1 to September30, 2010 provided by Weather Station of Fuhai County, we used FAO56 Penman-Monteith as the standard formula to compute ET_0, compared the differences and relations between such the method and other 4 calculation formulas, and analyzed the cause of the deviation, finally evaluated the applicability of computational method in North Xinjiang. The results showed that the calculation results by FA056 PM Method was approximate to that by FAO Penman method and IA method, of which the relative error was 9.26% and 13.51% respectively, the ET_0 results calculated by PT method and HS method were generally greater than the results by FAO56 PM, and their deviation was very obvious.

Development of A Reference Dose for BDE-47,99,and 209 Using Benchmark Dose Methods

Eleven recently completed toxicological studies were critically reviewed to identify toxicologically significant endpoints and dose-response information. Dose-response data were compiled and entered into the USEPA＇s benchmark dose software （BMDS） for calculation of a benchmark dose （BMD） and a benchmark dose low （BMDL）. After assessing 91 endpoints across the nine studies, a total of 23 of these endpoints were identified for BMD modeling, and BMDL estimates corresponding to various dose-response models were compiled for these separate endpoints. Thyroid, neurobehavior and reproductive endpoints for BDE-47, -99, -209 were quantitatively evaluated. According to methods and feature of each study, different uncertainty factor （UF） value was decided and subsequently reference doses （RfDs） were proposed. Consistent with USEPA, the lowest BMDLs of 2.10, 81.77, and 1698 I^g/kg were used to develop RfDs for BDE-47, -99, and -209, respectively. RfDs for BDE-99 and BDE-209 were comparable to EPA results, and however, RfD of BDE-47 was much lower than that of EPA, which may result from that reproductive/developmental proves to be more sensitive than neurobehavior for BDE-47 and the principal study uses very-low-dose exposure.

绿茶中联苯菊酯和氯氟氰菊酯残留检测质量控制基体标准物质的研制

目的:制备一批绿茶中联苯菊酯和氯氟氰菊酯基体标准物质。方法:以绿茶为研究对象,通过喷洒联苯菊酯和氯氟氰菊酯,样品经粉碎、过筛、均质、装瓶,通过均匀性、稳定性检验后,由3家实验室联合定值确定量值,并进行不确定度评估。结果:绿茶中联苯菊酯和氯氟氰菊酯的量值分别为(0.185±0.0197),(0.207±0.0466)mg/kg,k=2,置信区间为95%。结论:研制出的绿茶中联苯菊酯和氯氟氰菊酯基体标准物质足够均匀,足够稳定,定值结果可靠。

Quantum-Mechanical Information Content of Multiples Hartree-Fock Solutions. The Multi-Reference Hartree-Fock Configuration Interaction Method

The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited

基于双参考优化的壁画图像色彩还原

褪变色壁画图像的色彩还原研究可以促进壁画的保护和展示。壁画图像色彩还原旨在将退化壁画图像的色彩褪变区域还原为原有色彩。常规的基于单幅参考壁画图像的色彩还原方法难以选取与退化壁画图像相似的参考壁画图像,进而影响色彩还原质量。为此,提出一种基于双参考优化的壁画图像色彩还原方法。采用双参考策略,即使用2幅参考壁画图像对退化壁画图像进行色彩还原,利用图像优化模块抑制褪变色壁画图像中普遍存在的噪声、划痕等多重退化,通过编码器-解码器网络编码提取壁画图像多尺度特征,并构建特征融合模块优化壁画图像的多尺度特征。采用双参考指导模块计算参考壁画图像与退化壁画图像的语义对应置信度,以实现图像区域间的相似性匹配,并实现2幅参考壁画图像的风格融合。在此基础上,利用融合特征实现退化壁画图像的色彩还原。实验结果表明,该方法可以较准确地还原退化壁画图像色彩,同时能较好保持壁画图像原有的边缘结构信息,并且使用无参考图像质量评估指标对各个方法的还原壁画图像进行客观评估,与对比方法相比,该方法在客观评估指标上最多可降低12.2%。

高干扰矿集区大地电磁噪声抑制技术探索

大地电磁测深(MT)在矿产资源勘探方面应用广泛,但强人文电磁干扰严重制约了高质量的原始MT数据的获取。本文详细总结了国内常见电磁噪声源的类型,对其产生的电磁噪声特征进行分类分析;对国内外MT电磁噪声去噪方法进行对比,结合实际生产需求,总结了一套适用于高干扰矿集区快速有效的MT数据去噪施工与处理工艺。研究表明:Robust处理、远参考道技术和人工挑选是提高MT数据采集质量的有效和必要的手段,而通过理论计算,远参考站设置距离不小于3.56倍趋肤深度即可;在江苏洪泽盐盆矿集区开展的MT试验工作验证了该设定。

农产品检测用脱氧雪腐镰刀菌烯醇纯度标准物质的研制

[目的]本文旨在研制脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)国家级纯度标准物质,为农产品中DON的检测等工作提供物质基础。[方法]利用质量平衡法和定量核磁共振法对DON纯度标准物质进行纯度定值。质量平衡法包括采用液相色谱面积归一化法测定DON主成分含量,采用卡尔费休库仑法测定纯度标准物质中水分含量,采用顶空气相色谱-质谱法测定挥发性杂质含量,以及采用电感耦合等离子质谱法测定无机离子杂质含量。定量核磁共振法采用苯甲酸为内标,选择合适的共振峰,内标法定量标准物质的纯度,并对标准物质进行均匀性、稳定性检测和不确定度评估。[结果]质量平衡法的纯度定值结果为99.47%,定量核磁共振法定值结果为99.45%,最终所研制的DON纯度标准物质的纯度为99.5%,扩展不确定度为0.4%,均匀性良好,且满足12个月以上的稳定性要求。[结论]本试验所研制的DON纯度标准物质符合国家标准物质技术规范,目前已被批准为国家一级标准物质,并已被用于小麦、玉米等农产品实际检测过程中。

依据EP9-A3评价血清总蛋白常规方法和参考方法的可比性

目的评价血清总蛋白常规方法与参考方法的一致性,旨在为临床提供准确结果。方法采用血清总蛋白参考方法和常规方法同时测量GBW09186~188、RELA22A、22B、18A、18B、17A、17B、40份单人份血清样本,参考EP9-A3,将两种方法检测结果进行比对;参考EP14-A3文件,对常规方法使用的校准品进行互换性分析。结果参考方法测量标准物质和比对样本的偏倚为-1.66%~0.51%,常规方法测量偏倚为-2.34%~-0.30%,参考方法偏倚均小于常规方法。Bland-Altman图所有数据均匀地分布在均值附近且大部分(41/43)在95%置信区间(CI)内,说明两种方法有良好的一致性。3种回归分析中45g/L医学决定水平处的偏倚大于临床可接受范围,其余医学决定水平处的偏倚均小于临床可接受范围。常规方法使用的校准品测量值和其预测值的偏倚分别为1.23%、-1.65%,2个校准品均超出95%CI,校准品无互换性。结论血清总蛋白常规方法存在系统误差,且在低值处的正确度略有偏差。

强化特征图的无参考低光照图像增强

针对低光照图像质量不佳、夹杂噪声导致对比度和亮度不足、细节不清晰,且成对的低光照图像数据集获取成本过高的问题,在生物视觉马赫带效应的启发下,提出一种强化特征图的无参考低光照图像增强方法。使用强化滤波块(EFB)对图像和特征图进行特征强化,抑制噪声的同时强化特征细节,提高网络对特征的学习能力。将跳跃连接与空间注意力模块(ESA)结合,通过融合强化的浅层特征与深层特征来提取全局上下文信息和局部区域特征,有效保留了图像的色彩信息,避免细节丢失,提高网络的泛化能力。使用像素估计曲线调整低光照图像像素的动态范围,对其进行亮度增强。实验结果表明,经该算法处理后的图像在PSNR、SSIM、LPIPS和NIQE等指标上分别达到了17.709 dB、0.657、0.239和3.486,该方法相较于现有的主流算法能够更好地达到图像增强目的,有效地提升图像亮度和细节信息,同时保持图像的自然属性。

北斗坐标框架解算中的IGS参考站选站方法研究

首先从ITRF2020框架中筛选能接收北斗信号的站点;然后从数据完整性、卫星可见性、多路径误差等方面对站点观测数据质量进行分析,设定相应标准进行筛选;最后基于格网法提出一种既考虑均匀性又考虑数据质量和站点稳定性的选站方法。利用该方法优选72个全球均匀分布的测站作为北斗坐标框架解算中的IGS参考站。

自贡地区不同年龄阶段妊娠早期妇女甲状腺功能指标参考区间的建立

目的:采用间接法建立四川自贡地区健康妊娠早期妇女不同年龄阶段甲状腺激素测定的参考区间,为临床诊断和治疗提供依据。方法:选取自贡市第一人民医院妇产科建档的2019年1月至2021年12月健康妊娠早期妇女的数据,共1518例。根据孕妇年龄分为A组(<26岁)、B组(26~34岁)、C组(>34岁)3组,以2.5%至97.5%的百分位点数所在区域作为参考区间。对3个年龄阶段目标人群的促甲状腺激素(TSH)、总三碘甲状腺原氨酸(TT3)、总甲状腺素(TT4)、血清游离三碘甲状腺原氨酸(FT3)和血清游离甲状腺素(FT4)这5项甲状腺激素数据进行统计分析。结果:不同年龄妊娠早期妇女的TSH、FT3和FT4这3项指标之间无统计学差异,3组年龄合并的参考区间分别为TSH(0.12~3.81 mIU/L)、FT3(2.20~5.03 pmol/L)、FT4(4.79~16.13 pmol/L);不同年龄的TT3、TT4水平有统计学差异,其中年龄小于26岁的妊娠早期妇女的TT3、TT4的参考区间分别为1.04~2.78 nmol/L和91.80~204.88 nmol/L,而年龄大于26岁的妊娠早期妇女的TT3、TT4的参考区间分别为1.04~2.55 nmol/L和82.70~190.00 nmol/L。各指标年龄组A、B、C组与非妊娠组比较,差异均有统计学意义(P<0.05)。结论:建立的自贡地区不同年龄阶段妊娠早期妇女甲状腺激素5项指标参考区间,可为临床疾病诊断、治疗和预后判断提供参考。

基于动态配气技术的气体标准物质研制进展

气体标准物质作为气体成分测量的计量标准,在气体检测中具有不可或缺的重要作用。而如何制备高精度、量值准确、种类多样的气体标准物质,一直是气体计量研究工作中的挑战重点和热门领域。经过多年的发展,在气体标准物质的生产中,目前常用的配气方法分为静态法和动态法两种。其中静态法由于其自身原理缺陷存在一定的应用限制。与静态配气法相比,动态配气法能够在更宽的浓度范围内产生更大数量的气体标准物质,且具有消除容器管壁吸附等优势,目前在气体标准物质配制中的势头强劲。针对目前常见的动态配气技术从配气原理以及目前在气体计量工作中的研究进展两个方面进行了系统的总结阐述,希望能对相关专业从业者以及不同领域的科研工作者将气体标准物质动态配气技术运用于实际工作提供参考。

淮北平原36种参考作物蒸散量估算方法适用性研究

为分析不同参考作物蒸散量估算方法在淮北平原的适用性,以FAO56 Penman-Monteith(FAO56PM)模型为标准,基于五道沟实验站2009-2022年气象观测数据,选取6种统计指标,从日、月尺度综合分析。结果表明,所有方法中,日尺度下FAO24Penman(FAO24PM)法、1996 KiM-Berly Penman(K-P)法、Pristley-Taylor(P-T)法最优,月尺度下FAO24PM法、P-T法、Debruin-Keijman(D-K)法最优;综合法最优,其次依次为辐射法、质量传输法和温度法;综合法中FAO24PM法最优,辐射法中P-T法最优,温度法中FAO24BC法最优,质量传输法中Mahringer法日尺度下最优,Trabert法月尺度下最优。因此,当数据资料充足时推荐FAO24PM法,资料不齐全时推荐P-T法、FAO24BC法、Mahringer法(日尺度)或Trabert法(月尺度)。

间接法建立新疆克拉玛依地区常规肝功能和血脂生化项目参考区间

目的采用间接法利用大数据建立新疆克拉玛依地区常规肝功能和血脂生化项目参考区间。方法收集新疆克拉玛依市中西医结合医院(市人民医院)2018-2020年体检人群数据,并对数据进行删减、去重、正态性检验、数据对数转换和离群值剔除。采用Z检验考察参考区间年龄和性别分区,应用非参数法计算参考区间,并以参考变化值(RCV)作为验证依据验证该研究中建立的参考区间可靠性。结果纳入分析的有效数据为:总蛋白(TP)27492例,丙氨酸氨基转移酶(ALT)60798例,天冬氨酸氨基转移酶(AST)37080例,甘油三酯(TG)30287例,总胆固醇(TC)35778例,高密度脂蛋白胆固醇(HDL-C)34194例,低密度脂蛋白胆固醇(LDL-C)33087例,白蛋白(ALB)37893例。ALT、AST和TG的参考区间存在性别差异(Z>Z*)。新疆克拉玛依地区常规肝功能和血脂生化项目参考区间为TP 69~85 g/L,ALB 41~51 g/L,TC 3.06~6.00 mmol/L,LDL-C<3.81 mmol/L,HDL-C 0.87~1.91 mmol/L;ALT男性为9~42 U/L、女性为7~39 U/L,AST男性为14~30 U/L、女性为12~28 U/L,TG男性为0.55~2.20 mmol/L、女性为0.47~2.10 mmol/L。除ALB外,其余指标参考区间与现行参考区间相比,均小于RCV。结论间接法建立的肝功能和血脂生化项目的参考区间简单、可靠,可在该地区实验室推广和应用。

ZnS分子激发态光谱性质的理论研究

采用考虑了戴维森修正的多参考组态相互作用(MRCI+Q)方法计算了ZnS分子能量最低的四条解离极限相关的18个Λ-S态的电子结构,并给出了势能曲线(PECs).计算中纳入了相对论效应和Zn原子3d轨道的芯-价电子关联效应.通过求解一维径向Schr?dinger方程,拟合出了一些典型束缚态的光谱常数,与之前的实验数据符合得很好.还计算了ZnS分子的永久偶极矩(PDMs),通过对PDMs的分析,阐明了ZnS分子中Zn原子与S原子的成键特性与分子极性.借助耦合矩阵元说明了电子态之间的扰动作用和预解离机制.最后,计算了^(1)Σ^(+)-^(1)Σ^(+)和^(1)Π-^(1)Σ^(+)态的跃迁偶极矩(TDMs)、Franck-Condon因子(FCFs)和振动能级信息以及自发辐射寿命.

任务多标准优先级排序方法综述

任务的多标准优先级排序(multi-criteria priority ranking)涉及在可能存在冲突的多个标准下为大量任务计算优先级,以便决策者能够高效地分配资源,优先处理更为关键的任务,进而提高整体工作效率。经过近二十年的持续修改与扩展,目前优先级排序领域已展现众多成熟的经典方法;且随着大数据时代的到来,采用新兴技术的排序方法也开始涌现。为了帮助决策者根据不同情境下的优先级排序需求来评估和选择最适合特定应用场景的多标准优先级排序方法,文章阐释了不同多标准优先级排序方法在标准间的可替代性、优缺点、数据输入/输出要求、适用场景等方面的差异,将当前多标准任务优先级排序方法分为:全聚合法、劣势排序法、参考水平法以及基于数据处理技术的优先级排序方法4大类,详细讨论了各类别下代表性方法的基本原理、最新研究结果和优缺点;并总结了当前优先级排序方法研究的热点,包括层次分析法、模糊理论及人工智能辅助排序技术,提出其未来研究方向,涵盖了AI辅助的大数据排序优化、增强排序稳定性以及智能偏好识别。