Improvements to the fuzzy mathematics comprehensive quantitative method for evaluating fault sealing

Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy mathematics is improved based on a previous study.First,the single-factor membership degree is determined using the dynamic clustering method,then a single-factor evaluation matrix is constructed using a continuous grading function,and finally,the probability distribution of the evaluation grade in a fuzzy evaluation matrix is analyzed.In this study,taking the F1 fault located in the northeastern Chepaizi Bulge as an example,the sealing properties of faults in different strata are quantitatively evaluated using both an improved and an un-improved comprehensive fuzzy mathematics quantitative evaluation method.Based on current oil and gas distribution,it is found that our evaluation results before and after improvement are significantly different.For faults in＂best＂and＂poorest＂intervals,our evaluation results are consistent with oil and gas distribution.However,for the faults in＂good＂or＂poor＂intervals,our evaluation is not completelyconsistent with oil and gas distribution.The improved evaluation results reflect the overall and local sealing properties of target zones and embody the nonuniformity of fault sealing,indicating the improved method is more suitable for evaluating fault sealing under complicated conditions.

Mathematical modeling for dynamic stability of sandwich beam with variable mechanical properties of core

The paper is devoted to mathematical modelling of static and dynamic stability of a simply supported three-layered beam with a metal foam core. Mechanical properties of the core vary along the vertical direction. The field of displacements is for- mulated using the classical broken line hypothesis and the proposed nonlinear hypothesis that generalizes the classical one. Using both hypotheses, the strains are determined as well as the stresses of each layer. The kinetic energy, the elastic strain energy, and the work of load are also determined. The system of equations of motion is derived using Hamilton＇s principle. Finally, the system of three equations is reduced to one equation of motion, in particular, the Mathieu equation. The Bubnov-Galerkin method is used to solve the system of equations of motion, and the Runge-Kutta method is used to solve the second-order differential equation. Numerical calculations are done for the chosen family of beams. The critical loads, unstable regions, angular frequencies of the beam, and the static and dynamic equilibrium paths are calculated analytically and verified numerically. The results of this study are presented in the forms of figures and tables.

模糊数学综合评价结合响应面法优化竹笋汁饮品发酵工艺

该研究以清水竹笋罐头生产过程中产生的清水为原料,以发酵乳杆菌(Lactobacillus fermentium)与红茶菌为菌种复合发酵制备竹笋汁饮品。利用单因素试验、模糊数学综合评价结合响应面法对其发酵工艺进行优化,并对其理化指标、微生物指标及抗氧化性进行检测分析。结果表明,竹笋汁饮品的最佳发酵工艺为:红茶菌添加量6%、发酵温度25℃、发酵时间2.5 d。在此优化条件下,竹笋汁饮品的色泽均匀,呈浅黄色的基底液,其感官评分为85.24分,固形物含量为6.13 g/L,pH为3.38,总糖含量为0.16 g/L,总酸含量为41.33 g/L,总酚含量为7.74 mg/L,总黄酮含量为0.066 mg/m L;益生菌活菌数为3.5×107CFU/g,大肠菌群、沙门氏菌及霉菌未检出,说明其理化指标及微生物指标均符合T/CASME 435—2023《益生菌发酵植物饮料》。竹笋汁饮品对1,1-二苯基-2-苦基肼(DPPH)自由基清除率为64.03%,羟自由基(·OH)清除率为46.62%,说明其具有一定的抗氧化能力。

初烤烟叶主脉与叶片的吸附等温线及其热力学性质研究

为探究初烤烟叶主脉与叶片在吸湿过程中所表现出的水分吸附特性,测定初烤烟叶主脉与叶片在环境温度20、25、30、35、40℃以及环境相对湿度50%、60%、70%、80%、90%下的吸湿情况,绘制初烤烟叶主脉与叶片的吸附等温线,采用5种常用的农产品吸附等温线模型对试验数据进行拟合,并在此基础上探究初烤烟叶主脉与叶片的热力学性质。结果表明,初烤烟叶主脉与叶片的吸附等温线属于Ⅲ型等温线,在环境相对湿度相同的条件下,初烤烟叶主脉与叶片的平衡含水率随环境温度的升高而降低。MHAE模型是描述初烤烟叶主脉与叶片吸附等温线的最佳模型,决定系数(R^(2))为0.99877~0.99905,平均相对百分率误差(MRE)为1.45515%~2.94968%。热力学性质研究结果表明,在平衡含水率发生变化时,初烤烟叶主脉与叶片的净等量吸附热(Q_(st))与微分吸附熵(ΔS)有相似的变化趋势,均随平衡含水率的升高而下降,且两者与温度之间都没有明显关系。在初烤烟叶主脉与叶片的水分吸附过程中,熵-焓补偿理论也同样存在并适用,并且水分吸附过程是自发的由焓所驱动的反应。综上,初烤烟叶主脉与叶片在水分吸附过程中的热力学性质较为相似,MHAE模型适合用来描述初烤烟叶主脉与叶片在温度20~40℃的吸附等温线。

最小支配阈值集问题的降阶回溯算法

图论中的最小支配阈值集问题是组合优化中的一个NP-Hard问题,该问题是最小支配集问题的一个扩展问题。基于给定无向图G=(V,E)和阈值r的最小支配阈值集问题进行研究,首先得出一些可以降低问题规模的数学性质并证明,利用这些性质可以减小问题规模,降低问题的求解难度;然后设计出上界子算法、下界子算法和降阶子算法,并基于这些子算法提出了一种可以减小问题规模同时得到最优解的降阶回溯算法BAR;最后,通过一个示例分析和若干随机算例测试验证了降阶回溯算法可有效降低问题的求解难度。

考虑容量和成本的最大最小分散度选址问题的降阶回溯算法

最大最小分散度问题可简单描述为:在给定的集合中选择包含固定元素个数的子集,使得该子集中的元素在给定距离度量下的最小距离最大;该问题在生产生活中有广泛的应用.近些年来,该问题的一种考虑容量下限和成本上限的变体开始引起学者们的关注,并已被证明为NP-Complete问题.基于考虑容量和成本的最大最小分散度选址问题进行研究,首先提出该问题的数学性质并证明,利用这些性质可以减小问题规模或缩减搜索空间,以加快问题的求解速度,然后设计了上下界子算法及降阶子算法;基于这些子算法提出一种可大幅缩减搜索空间并能得到最优解的降阶回溯算法.通过分析和求解一个示例来阐述该算法的原理和执行过程,并通过随机算例测试、算法对比分析和案例分析进一步验证了该算法的可行性和有效性.结果表明该算法可有效通过大幅缩减搜索空间加快问题的求解速度.

O/W乳化体系化妆品感官评价与仪器分析相关性研究进展

为满足消费者的需求和愿望,在优化产品时,需要做感官评价。以“人”作为测量工具的感官评价需要控制个体差异性,而流变学测量和质构分析等仪器测量方法,操作简单、成本更低、结果客观可重复。文章查阅了国内外化妆品感官评价和仪器分析表征相关的文献,介绍了描述性感官分析中各感官属性的定义,总结与感官属性强相关的仪器参数和测试方法,列出部分感官属性与仪器参数的拟合方程,为化妆品在开发阶段的配方设计和筛选提供科学依据。提出部分感官属性和仪器参数的相关性研究尚不完整,后续研究还应考虑不同皮肤类型的消费者在使用化妆品后感官属性的差异,通过仪器分析对不同皮肤类型感官属性预测的研究方向进行展望。

含不饱和脂肪酸调制乳粉配方优化及理化性质分析

该试验针对乳固体、低聚木糖、不饱和脂肪酸进行调制乳粉的配方设计及理化性质分析,旨在设计一款满足血脂异常人群营养需求的含不饱和脂肪酸的调制乳粉。利用3T3-L1前脂肪细胞考查调制乳粉抑制脂滴积累的程度结合模糊数学感官评价法综合分析筛选调制乳粉的最优配方,使其具有良好的感官品质,并对最优配方奶粉进行理化性质分析,确保满足国标对调制乳粉要求。结果表明,调制乳粉配方中乳固体添加量为72%,低聚木糖添加量为2%,不饱和脂肪酸添加量为22%。蛋白质含量26.17 g/100 g、脂肪含量26.74 g/100 g、复原乳酸度10.50°T、杂质度8 mg/kg、水分含量3.02 g/100 g。在此条件下制得的乳粉呈乳黄色、冲调性较好、具有浓郁乳香味,与全脂奶粉相比显著降低3T3-L1前脂肪细胞面积(P<0.05),对脂肪细胞增殖有抑制效果。

马尾松、杉木木粉增强PE-HD复合材料的力学和蠕变性能

针对木塑复合材料(WPCs)在长期负载下的蠕变行为导致力学失效的问题,为明确WPCs的力学性能和蠕变特性,采用两步成型挤出法,制备7种马尾松木粉和杉木木粉增强高密度聚乙烯复合材料,分析和比较两种木粉的添加比例对WPCs的弯曲性能、动态力学性能和短期蠕变性能的影响,采用数理模型对WPCs蠕变随时间的变化进行模拟。结果表明,增强木粉中杉木木粉的含量越高,WPCs的弯曲性能越好,但是蠕变性能变差。杉木木粉在增强木粉中的质量分数为83.3%时,WPCs的储能模量最大,马尾松木粉含量逐渐减少时,WPCs的储能模量和损耗角正切值分别增大和减小。提高马尾松木粉的添加量有效地降低了WPCs在10%应力水平下的24 h应变值。Findley模型和ExpAssoc函数拟合WPCs的蠕变行为效果较好,修正后的ExpAssoc模型模拟效果更优,7种WPCs在10%应力水平下的拟合修正系数R2均在0.99以上。

高温后不同降温方式对600MPa级高强钢筋力学性能的影响

本文研究了高温后不同降温方式对600MPa级高强钢筋表观形貌与力学性能的影响,分析了其应力-应变曲线、屈服强度、极限强度、断后伸长率以及最大力下总伸长率等力学响应的变化规律。试验结果表明:自然降温与炉内降温方式对高强钢筋力学性能的影响接近,而浸水降温方式对高强钢筋力学性能的影响较大,尤其是在经历800℃高温后,其各项力学性能变化显著。此外,本文还建立了高温后不同降温方式下600MPa高强钢筋的数学模型,能够较好地预测其力学性能。

Rheological properties of oil-based drilling fluids at high temperature and high pressure

The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.

VARIATION PATTERN OF WOOD PROPERTIES OF NATURALCUNNINGHAMIA LANCEOLATA

In thes paper, the variation pattffe of wood Prpebo was edied for natural Cunninghamia lanceolata. The mathematical models of property were obtained on tracbeidlength, microfibril angle, late wood percdsgn, growth ring width and growth ring dsisity in the radial direction. The interrelation were analynd between tracheid length and microfibril angle. The result can provide sciatilic theory basis for wood utilhaion and early prediction of wood properties .

Mathematical Index for Evaluating Disperse Dyes Levelness of Superfine Polyester Fabric

The dyeing deference between the superfine and the con-ventional polyester fabric is discussed. The major threefactors affecting the level dyeing property of superfinepolyester-initial adsorption rate, desorption rate andinterface migration rate of dyestuffs at 70℃ are studied.The levelness improves considerably with decreased ini-tial adsorption rate, increased desorption rate and inter-face migration rate. And then a mathematical indexbased on them is established. The evaluation to dispersedyes resulting from it corresponds with their perfor-mance during industrial process. As new definitions, ini-tial adsorption rate and desorption rate of dyestuffs arefirstly introduced.

A Mathematical Model for Juice Extraction from Chopped Sweet Sorghum

Juice extraction from chopped sweet sorghum is an example of flow through porous media. Darcy’s law is often used to express this type of phenomenon. However, using Darcy’s law to construct a mathematical model to predict juice extraction from chopped sweet sorghum is difficult, because the volume of the porous media changes during the pressing operations. A mathematical model was developed from fundamental analysis to predict the juice extraction ratio of chopped sweet sorghum, and experiments were conducted to verify the model. An experimental piston-cylinder assembly was developed to conduct the validation experiments. The parameters in the developed model were estimated by using non-linear regression analysis from the experimental data. Plots of the mathematical model agreed well with experimental data. R^2（coefficient of determination） values for all the regressions studied were higher than 0.99. Results showed that the juice extraction ratio of chopped sweet sorghum approached an asymptote with a maximum value that depended on the physical form of the sample. The model could help in understanding the mechanics of juice extraction from chopped sweet sorghum.

New Asymmetric Model for Predicting Ternary Thermodynamic Properties

The prediction of the thermodynamic properties of ternary systems from the properties of their sub-binary systems is of great importance to phase diagram calculations. In the present study, a new asymmetric model which has more clear physical significance has been developed for evaluating the ternary thermodynamic properties from its three binary components. The model is considered to be rigorous in the case where the pseudobinary systems of fixed X2/X3 are regular are regular solution. The application of new model to the prediction of ternary enthalpies of mixing for Bi-Ga-Sn, Au-Ag-Sn and NaCl-KCl-CaCl2 systems shows that the calculated results by new model are closer to experimental data than those by Toop's model.

温度耦合驱动下土壤–地下水有机污染物迁移规律与模拟研究进展

场地土壤–地下水有机污染空间分布受温度场、水动力场、化学场和生物场等多场控制。明晰有机污染物在土壤–地下水系统中的空间分布规律和驱动机制,定量模拟污染迁移过程,是有效开展污染控制与修复的前提。在众多的影响因素中,温度通过改变有机污染物的理化性质及多相流、化学/生物作用驱动参数,进而影响其在土水介质中的迁移及空间分布。本文综述了有机污染物理化性质(密度、黏度、溶解度)和有机污染化学/生物驱动(挥发、吸附和生物降解)关键参数与温度之间的解析关系,及考虑温度影响的土壤–地下水中有机污染传质过程模拟的研究进展,并针对目前模拟研究的不足提出了耦合温度场的土壤–地下水有机污染物迁移数学模型,为定量探究温度耦合驱动下的有机污染物迁移转化过程和规律提供参考。

Mathematical Modeling of Heat Flux Distribution in Raw Cotton Stored in Bunt

The scientific article examines the physical and mechanical properties of raw cotton stored in buntings in cotton palaces. Because during the storage of raw cotton in bunts, some of its properties deteriorate, some improvements. Therefore, the mathematical modeling of storage conditions of raw cotton in bunts and the physical and mechanical conditions that occur in it is of great importance. In the developed mathematical model, the main factor influencing the physical and mechanical properties of raw cotton is the change in temperature. Due to the temperature, kinetic and biological processes accumulated in the raw cotton in Bunt, it can spread over a large surface, first in a small-local state, over time with a nonlinear law. As a result, small changes in temperature lead to a qualitative change in physical properties. In determining the law of temperature distribution in the raw cotton in Bunt, Laplace’s differential equation of heat transfer was used. The differential equation of heat transfer in Laplace’s law was replaced by a system of ordinary differential equations by approximation. Conditions are solved in MAPLE-17 program by numerical method. As a result, graphs of temperature changes over time in raw cotton were obtained. In addition, the table shows the changes in density, pressure and mass of cotton, the height of the bun. As the density of the cotton raw material increases from the top layer of the bunt to the bottom layer, an increase in the temperature in it has been observed. This leads to overheating of the bottom layer of cotton and is the main reason for the deterioration of the quality of raw materials.

基于模糊数学感官评价、理化特性与电子舌的橄榄鲜食品质分析

为全面、客观地评价和分析不同品种(系)橄榄果实鲜食品质,建立品质特征快速检测方法,本研究以10个不同品种(系)橄榄果实为研究对象,通过结合模糊数学感官评价方法、多频脉冲电子舌技术及相关品质理化指标测定,分析橄榄果实品质与理化指标的相关性,并构建橄榄鲜食品质预测模型,通过决定系数R^(2)与平均相对误差δ对模型进行评价。德尔菲法结合九级标度法构建的感官评价结果表明,回甘度和涩味度的总权重达76.9%,是影响橄榄鲜食的主要品质特性;感官模糊数学综合评价结果与理化指标的相关性分析结果表明酚糖比与果实回甘度、涩味度呈极显著相关(P<0.01);通过主成分分析优化得到多频脉冲电子舌辨识区分不同橄榄品质的最佳电极组合为钯(10 Hz)、钛(10 Hz)。进一步利用该电极工作组合的电子舌信号特征值与感官评价得分、理化指标进行多元逐步回归建模,发现多频脉冲电子舌特征信号值能够对橄榄理化指标进行有效预测,其中酚糖比(R^(2)=0.832、δ=10.89%)和可溶性糖质量分数(R^(2)=0.831、δ=5.75%)的预测效果最好,其次为总酚质量分数(R^(2)=0.783、δ=12.08%);化学指标(酚糖比)、电子舌信号特征值构建的回归模型均可实现对感官评价得分的有效预测,化学指标拟合模型预测效果优于电子舌信号特征值的拟合模型,但模型拟合性一般,R^(2)分别为0.589、0.542。本研究结果为橄榄品质特征快速检测,及优良单株选育快速判定提供了实践参考。

沁水盆地榆社-武乡区块深部煤层气赋存条件及开发甜点预测

沁水盆地榆社-武乡区块深部煤层气富集成藏受多因素耦合作用,深部条件的特殊性使其选区不能完全参照浅部地质评价技术,亟需从地质-工程角度对区块进行开发甜点区优选,满足实际生产需要。以3#煤层为目的层,从构造与水动力、地应力、煤储层含气性、孔渗性、煤体结构及力学性质等条件出发,剖析深部煤层气富集特点,运用多层次模糊数学评价法对区块进行甜点优选。结果表明:3#煤层煤体结构以Ⅰ类原生结构煤为主,具有泊松比小、弹性模量大、脆度指数高、含气性良好的特点,煤层厚度0.25~5.19 m,平均1.59 m,含气量16.5~25.5 m^(3)/t,平均19.84 m^(3)/t;研究区褶皱与断层较为发育,煤层顶板岩性以泥岩为主,地下水径流条件差;深部地应力状态表现为σV(垂直压力)>σH(最大水平压力)>σh(最小水平压力);3#煤层属低孔、低渗储层,微小孔发育,渗透率平均为0.183×10^(-3)μm^(2);根据综合评价得分划分4类甜点区,其中区块中西部和L1302井附近为开发甜点区。研究成果对榆社-武乡区块深部煤层气下一步勘探开发具有指导意义。

基于“一心二思三维”模式的高等数学教学创新实践

为实现课程育人、创建一流课程,构建了“一心二思三维”模式:教学理念上遵循“一心”原则,以学生为中心,注重兴趣导向与结果导向,组织教学活动;教学设计上遵循“二思”原则,将数学思想方法与课程思政有机结合,实施课程育人;教学内容上遵循“三维”原则,即数学理论、应用和创新三个维度,改进知识体系.基于该模式进行了教学改革实践,并给出了若干案例和教学活动设计.