IMPROVEMENT OF THE PLOT METHOD OF FATIGUE LIFE PREDICTION FORMULA

The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and high cycle fatigue life is proposed and deduced, which has adopted more accurate SN curve relationship——WeibullSN curve formula. The solution of the new formula is given, too. In addition, an example has been calculated and proved in practice. The results of the new formula and the old one are given and compared.

Study on Surface Plotting Methods in Parts Plotting

According to the factors that confirm the shape of surface, it is classified into two categories： arc surface and curve surface The method to confirm the category of surfaces and the plotting methods are discussed in this paper, which provide guidance for parts plotting.

Thermal kinetic analysis of a complex process from a solid-state reaction by deconvolution procedure from a new calculation method and related thermodynamic functions of Mn_(0.90)Co_(0.05)Mg_(0.05)HPO_4?3H_2O

Three individual peaks of thermal solid-state reaction processes of the synthesized Mn0.90Co0.05Mg0.05HPO4?3H2O were observed corresponding to dehydration I,dehydration II and polycondensation processes.An alternative method for the calculation of the extent of conversion was proposed from the peak area of the individual DTG peak after applying the best fitting deconvolution function(Frazer–Suzuki function).An iterative integral isoconversional equation was used to compute the values of the apparent activation energy Eαand they were found to be 65.87,78.16 and 119.32 kJ/mol for three peaks,respectively.Each individual peak was guaranteed to be a single-step kinetic system with its unique kinetic parameters.The reaction mechanism functions were selected by the comparison between experimental and model plots.The results show that the first,second and final individual peaks were two-dimensional diffusion of spherical symmetry(D2),three-dimensional diffusion of spherical symmetry(D3)and contracting cylinder(cylindrical symmetry,R2)mechanisms.Pre-exponential factor values of 3.91×106,1.35×107 and 2.15×107 s?1 were calculated from the Eαvalues and reaction mechanisms.The corresponded standard thermodynamic functions of the transition-state(activated)complexes were determined and found to agree well with the experimental data.

A Technique to Analyse Succession Data from Permanent Plots

Data from vegetation succession study is usually a matrix of plot × species × time.It is difficult to analyse this kind of data at present.A simple technique,clustercentering ordination is described in this paper,which can be used to analyse such a matrix directly.The data of 5 permanent plots in 7 years of inlands and grasslands in Kootwijki,the Netherlands,is analysed using this method as an application example.The results obviously illustrate the trend,direction and speedof community succession and can be easily interbrated.This suggests that clustercentering ordination is an effective and time-saving technique in study of vegetation succession.

Application of SWAT99.2 to sensitivity analysis of water balance components in unique plots in a hilly region

Although many sensitivity analyses using the soil and water assessment tool(SWAT) in a complex watershed have been conducted, little attention has been paid to the application potential of the model in unique plots. In addition, sensitivity analysis of percolation and evapotranspiration with SWAT has seldom been undertaken. In this study, SWAT99.2 was calibrated to simulate water balance components for unique plots in Southern China from 2000 to 2001, which included surface runoff, percolation, and evapotranspiration. Twenty-one parameters classified into four categories, including meteorological conditions, topographical characteristics, soil properties, and vegetation attributes, were used for sensitivity analysis through one-at-a-time(OAT) sampling to identify the factor that contributed most to the variance in water balance components. The results were shown to be different for different plots, with parameter sensitivity indices and ranks varying for different water balance components. Water balance components in the broad-leaved forest and natural grass plots were most sensitive to meteorological conditions, less sensitive to vegetation attributes and soil properties, and least sensitive to topographical characteristics. Compared to those in the natural grass plot, water balance components in the broad-leaved forest plot demonstrated higher sensitivity to the maximum stomatal conductance(GSI) and maximum leaf area index(BLAI).

A Significant Look at the Effects of Persian Gulf Environmental Conditions on Sound Scattering Based on Small Perturbation Method

The main goal of this paper is to investigate sound scattering from the sea surface, by Kuo＇s small perturbation method （SPM）, in the Persian Gulf＇s environmental conditions. Accordingly the SPM method is reviewed, then it is demonstrated how it can accurately model sound scattering from the sea surface. Since in Kuo＇s approach, the effects of surface roughness and sub-surface bubble plumes on incident sounds can be studied separately, it is possible to investigate the importance of each mechanism in various scattering regimes. To conduct this study, wind and wave information reported by Arzanah station as well as some numerical atmospheric models for the Persian Gulf are presented and applied to examine sound scattering from the sea surface in the Persian Gulf region. Plots of scattering strength by Kuo＇s SPM method versus grazing angle for various frequencies, wave heights, and wind speeds are presented. The calculated scattering strength by the SPM method for various frequencies and wind speeds are compared against the results of critical sea tests 7 （CST-7）. The favorable agreement achieved for sound scattering in the Persian Gulf region is indicative of the fact that the SPM method can quite accurately model and predict sound scattering from the sea surface.

A Study on Description Methods of Sediment Transport Modulus in Small Watersheds

[Objective]This study aimed to clear the advantages,disadvantages and applicability of various analysis methods to assess sediment transport modulus in small watersheds using the multi-year observation data. [Method]Four methods,including the statistical eigenvalues,depolarized arithmetic mean,frequency of erosion intensity and box-whisker plots were applied into calculation of sediment transport modulus in four small watersheds,and then the results of the methods were compared to to filter a method with the widest applicability and scientific validity. [Result] The statistical arithmetic mean and median could hardly represent the concentration and general level of multi-year sediment transport modulus. Although the depolarized arithmetic mean had the tendency of reflecting the general level of data,it lost the extreme value and its information for making decision. The frequency of erosion intensity grade reflected the distribution of data in intensity classification. Box-whisker plot could show the concentration,dispersion and the number of abnormal data. [Conclusion] Multiple methods can be combined to comprehensively and objectively characterize the multi-year sand transport modulus due to their advantages and disadvantages. Additionally,box-whisker plot has good objectivity and applicability in displaying the multi-year data of small watershed.

Assessment of the State of Forests Based on Joint Statistical Processing of Sentinel-2B Remote Sensing Data and the Data from Network of Ground-Based ICP-Forests Sample Plots

The research was carried out on the territory of the Karelian Isthmus of the Leningrad Region using Sentinel-2B images and data from a network of ground sample plots. The ground sample plots are located in the studied territory mainly in a regular manner, laid and surveyed according to the ICP-Forests methodology with some additions. The total area of the sample plots is a small part of the entire study area. One of the objectives of the study was to determine the possibility of using the k-NN (nearest neighbor method) to assess the state of forests throughout the whole studied territory by joint statistical processing of data from ground sample plots and Sentinel-2B imagery. The data of the ground-based sample plots were divided into 2 equal parts, one for the application of the k-NN method, the second for checking the results of the method application. The systematic error in determining the mean damage class of the tree stands on sample plots by the k-NN method turned out to be zero, the random error is equal to one point. These results offer a possibility to determine the state of the forest in the entire study area. The second objective of the study was to examine the possibility of using the short-wave vegetation index (SWVI) to assess the state of forests. As a result, a close statistically reliable dependence of the average score of the state of plantations and the value of the SWVI index was established, which makes it possible to use the established relationship to determine the state of forests throughout the studied territory. The joint use and statistical processing of remotely sensed data and ground-based test areas by the two studied methods make it possible to assess the state of forests throughout the large studied area within the image. The results obtained can be used to monitor the state of forests in large areas and design appropriate forestry protective measures.

心电散点图解析策略之向量平移法

向量平移法是在充分了解Lorenz散点图与差值散点图的作图原理及其内在联系的基础上,派生出来的两图合参的分析方法,体现了Lorenz散点图与差值散点图的优势互补关系。向量平移法不仅适用于二维Lorenz散点图与二维差值散点图的综合分析,也适用于三维Lorenz散点图与三维差值散点图的综合分析。有向临界连通图是闭合的向量环,表明差值散点图满足向量守恒定律;正确标注有向临界连通图是向量平移的前提。疑难复杂病例的散点图分型复杂、规律性较隐蔽,利用两图合参的向量平移法能够充分揭示心电大数据的内在规律,特别是差值散点图特征点集互不重叠,能更好地实现编辑、选图等分析操作,使快速准确地分析疑难复杂动态心电图成为可能。

荒漠草原灌丛转变过程土壤水分亏缺空间特征及影响因素

草地灌丛化对生态系统结构、功能与服务产生重要影响,目前已经认识到其对土壤水分的负面影响,但还缺乏其在区域尺度的定量评价及其驱动机制研究。在宁夏荒漠草原选取43块成对样地(即荒漠草地和灌丛地),引入样地土壤水分相对亏缺指数(PCSWDI)评价荒漠草原向灌丛转变后土壤水分亏缺空间格局现状及其驱动因子。结果表明:荒漠草原转变为灌丛后0~100 cm和100~200 cm土壤含水量分别显著下降了27.80%和57.92%,0~100 cm灌丛地的PCSWDI显著低于荒漠草地,表明0~100 cm灌丛地目前不存在土壤水分亏缺现象。地统计学分析表明,荒漠草地和灌丛地的0~100 cm土壤水分相对亏缺指数的结构方差比分别为94.73%和95.29%,均属于强空间自相关,主要受结构性因子控制。此外,地理探测器的因子探测发现0~100 cm土壤储水量、坡向和田间持水量是影响灌丛地土壤水分相对亏缺指数的主导因子;交互探测表明,灌丛地0~100 cm土壤水分相对亏缺指数空间分异是多因子共同作用的结果。尽管分析得到0~100 cm灌丛地不存在土壤水分亏缺,但100~200 cm土壤含水量显著下降已经预示了深层土壤水分的消耗。因此,干旱半干旱地区的植被恢复必须考虑其植被承载力和水分阈值,基于自然的解决方案可能是未来植被恢复的主流思路。

低载波比牵引系统的感应电机特征根离散化模型研究

在大功率和高速电机驱动领域,电机控制系统将运行于低载波比工况。传统的一阶欧拉、二阶双线性等降阶离散化模型在低载波比下由于离散化误差过大,对应的状态观测将出现幅值和相位的稳态误差,严重时甚至出现发散不收敛现象。针对上述问题,该文提出了感应电机特征根离散化模型。通过构建感应电机的复矢量模型状态空间方程,将满秩的状态转移矩阵进行对角化,得到状态转移矩阵的精确离散化结果,该模型在低载波比时仍具有较高的离散化精度。同时,提出了一种基于伯德图的离散化误差定量分析方法,通过定量对比不同离散化模型和连续域模型之间观测变量的幅值和相位误差,从理论上证明了提出方法的优越性。最后,通过仿真和实验验证了上述感应电机特征根离散化模型在低载波比下均具有良好的稳态精度与暂态跟随性能。

基于Cesium实现数字露头实景三维模型地层要素标绘

地质露头在地质研究中极为重要,但其研究现状是不同地质研究人员对同一地质露头分多批次进行实地踏勘,各自进行的工作之间重复性过高但关联性不够,这样导致传统地质露头研究方式既耗费大量财力精力且效率不高。随着Web技术和实景三维建模技术的发展,在Web环境下开展数字露头实景三维模型研究与应用逐渐成为当前的研究热点,也使得在线数字露头研究成为了可能。同时,地层研究也是地质露头研究中的一个重要组成部分。因此,笔者面向Web环境,针对地层要素这一要点,研究了基于Cesium进行数字露头三维模型地层要素标绘的方法,通过调用和扩展Cesium库,设计了一套基于地层标绘线、面与文字的完整标绘方法,并详细阐述了其工作流程。以陕西府谷悬空寺露头为例,进行了一系列地层要素标绘,标绘效果较好。研究表明,笔者提出的针对数字露头的三维模型地层要素标绘方法具有标绘准确、高效、易用的特点,可以满足专业地质研究人员的工作需求,并对地质露头研究具有较大帮助。

双摆盘式大豆小区排种器的仿真优化

针对大豆小区排种器对不同品种大豆种子适应性差、清种困难的问题,研究设计了一种双摆盘式大豆小区育种排种器,其通过可拆型孔块及清种板提高品种适应性及清种率。对排种过程进行仿真模拟,并以型孔孔径和摆动频率为试验因素,以单粒率、多粒率和空粒率为试验指标设计二次通用旋转组合试验进行优化。得出优化指标为:型孔孔径为9~10 mm,摆动频率为0.5~1.2 Hz时,单粒率>60%,多粒率<30%,空粒率<15%。并以型孔孔径10 mm,摆动频率1.0 Hz为参数进行台架试验及田间试验,得到排种器的台架及田间试验的合格指数、重播指数和漏播指数分别为75.5%、16.9%、7.6%及71.4%、18.8%、9.8%,与优化结果基本一致。试验结果表明,排种器可满足小区育种播种的农艺要求,并为大豆小区精量播种机的设计提供一定的理论及参考依据。

卡尔曼滤波在海洋浮标数据预处理中的应用

【目的】优化自动化数据预处理方法,以提高海洋浮标数据质量。【方法】结合海洋浮标数据特征,提出了一种改进的自适应卡尔曼滤波自动化数据预处理方法,该方法通过箱型图进行异常值的检测,并采用方差受限的方法解决测量噪声导致的滤波发散问题。【结果与结论】海上工程应用和仿真实验结果表明,改进的算法计算开销低且不影响浮标系统的正常采集和数据融合工作,浮标数据采集率达100%,云数据中心数据接收率达97%。浮标采集的原始数据经过异常值修正和滤波降噪处理后,数据曲线更为平滑且符合随时间序列变化的规律,数据预处理效果良好。

几种基于随钻参数地层识别方法的对比分析

地层岩性的实时识别对及时调整钻井参数、有效控制井眼轨迹、寻找地下储层都具有十分重要的作用。与传统岩性识别方法相比,通过监测随钻参数变化进行岩性识别,具有便捷、高效、实时、准确、环保以及节能等优点。围绕基于随钻参数的地层岩性识别技术,按照煤矿勘探、油气藏开采等不同岩性识别应用领域对随钻参数进行分类;通过对随钻测控技术及装备的研究现状分析,介绍随钻参数采集及传输技术;介绍了机器学习算法、多元统计分析法、灰色关联法、交会图法的特点及应用情况;结合应用案例对4种基于随钻参数的地层识别方法进行对比分析。最终,归纳总结了随钻岩性识别研究的关键技术问题,分析了在研发及工程应用中存在的不足及面临的挑战,并给予建议。

国家冰冻人血清总蛋白标准物质在参考方法量值传递中的应用

目的评价以冰冻人血清总蛋白标准物质为校准品的参考方法测量结果的准确性。方法分别以SRM927e、SRM927f、GBW09186~188为校准品测量国际比对样本RELA 22A、22B,选出合适的校准品测量国际比对样本RELA 23A、23B、18A、18B、17A、17B和53份临床剩余单人份血清。参考美国临床实验室标准化协会(CLSI)EP09-A3文件对结果进行比对。结果以SRM927f为校准品,RELA 22A、22B的测量结果超出国际临床化学和检验医学联合会(IFCC)等效限,以SRM927e为校准品的测量结果在等效限范围内。以冰冻人血清总蛋白标准物质GBW09186~188为校准品的测量结果均在IFCC等效限范围内,其中以GBW09188的测量偏移最小;以GBW09188为校准品测量3年国际比对样本的测量偏移为-0.45%~0.45%,均在等效限范围内。以SRM927e、GBW09188为校准品的Bland-Altman一致性分析结果显示,所有数据均在95%可信区间(CI)内,2个校准品有较好的一致性;4种回归分析结果显示,各医学决定水平处的偏移均在临床可接受范围内。结论以冰冻人血清总蛋白标准物质GBW09188为校准品的血清总蛋白参考方法的测量结果准确可靠。

基于GWO-BiLSTM的岩性识别方法研究与应用

为解决常规岩性识别方法精度不高、耗时较长且受人为影响较大等问题,构建了基于GWO-BiLSTM的岩性识别方法。结合录井资料、岩心资料以及测井资料,采用常规方法对研究区进行岩性识别,效果较差,进而利用GWO-BiLSTM模型在研究区展开岩性识别工作。根据皮尔逊函数对各测井曲线与岩性进行分析,优选出相关系数绝对值大于0.3的测井曲线值作为输入特征,采用灰狼优化算法对BiLSTM超参数组合随机生成与更新,从而更加快速地获取最优解,进一步提高模型的效率以及准确率。实验表明,基于GWO-BiLSTM模型的岩性识别准确率达96%,与BiLSTM模型、RF模型、BP神经网络和SVM模型相比具有较高的准确率,验证了该模型在识别复杂岩性时的可靠性,并为复杂岩性识别提供了方法参考。

“观”与“演”互动下古典园林中场景-情节空间研究

古典园林观演以一种审美事件结构建立起参与主体与空间组织的关联,打破观看与表演二元对立的界限,引发对“观”与“演”交互机制下空间营建策略的思考。以可操作的设计方法确立现象学介入场所研究的途径:在主体“观”的视角下,将“演”作为客体对象,从“互动感知-识别定位-动态展开”三个维度细分二者互动交流与事件空间建构的过程,由此归纳出背景垫衬、焦点主导、山水阐发、琴画合一四种场景(scenes)建构逻辑,以及悬念闪回、活动联结、回环收束三种情节(plots)编排方式。旨在以“事件”的视角更新园林认知,为当代空间的场所营造提供“园林”的营运方式。

基于支持向量机算法的葡萄酒质量检测模型

随着我国经济的不断发展,葡萄酒作为一种悦人悦己的生活媒介已经登上大众餐桌。然而,葡萄酒的质量检测仍以品酒师品尝为主,已不能满足规模化、智能化的食品工业发展需求。为此,基于支持向量机算法对葡萄酒理化指标进行建模,利用R语言实现Box-plot法对异常值进行处理,同时对RBF核的支持向量机参数进行优化,最终得到一个精度达到96.46%的葡萄酒质量检测模型,为葡萄酒的质量控制提供了一条行之有效的途径。

两种从场地调查数据中分离土壤环境背景数据方法的比较

地块土壤环境背景值在我国土壤环境管理中具有重要作用,土壤环境背景含量数据可采用间接方法从土壤污染状况调查数据中分离获得。采用稳健正态概率Q-Q图法和标准阈值法两种间接方法,从研究案例数据和模拟数据中分离土壤环境背景数据,并对两种方法的有效性和适用性进行比较分析。案例地块土壤钴(Co)含量数据呈现双峰分布,来源于两个不同总体。模拟数据M_(1)和M_(2)来源于背景数据(B)和非背景数据(N_(1)或N_(2)),M_(1)由B和N_(1)组成,两者之间重叠较多,M_(2)由B和N_(2)组成,两者之间重叠较少。研究结果显示,对于案例地块数据,利用稳健正态Q-Q图法和标准阈值法分离出的土壤环境背景数据之间差异较小,且与采用背景参考区法获得的土壤环境背景数据具有相似的统计特征。对于模拟数据,采用标准阈值法和稳健Q-Q图法都可以有效地从模拟数据M_(1)和M_(2)中分离出背景数据,两种方法分离出的背景数据之间及其与B之间均没有显著差异,且模拟数据的不同重叠程度对分离背景数据的影响较小。但是由于采用标准阈值法分离出的背景数据与B更相近,且方法简单易操作,更适用于土壤环境背景数据的分离。该研究可为地块土壤环境背景数据的获取提供方法上的借鉴。