An improved model of partition curve based on accumulation normal distribution function

Extensive studies based on partition curve of gravity separation have been investigated. All created models are merely used to simulate density distribution at the same size fraction. However, they cannot be used to predictive distribution of materials depending on compound feature of density and size. According to this situation, an improved model of partition curve based on accumulation normal distribution, which was distinguished from conventional model of accumulation normal distribution for partition curve, was proposed in this paper. It could simulate density distribution at different size fractions by using the density-size compound index and conflating the partition curves at different size fractions as one partition curve. The feasibility of three compound indexes, including mass index, settlement index and transformation index, were investigated. Specific forms of the improved model were also proposed. It is found that transformation index leads to the best fitting results, while the fitting error is only 1.75 according to the fitting partition curve.

Attenuation-type and failure-type curve models on accumulated pore water pressure in saturated normal consolidated clay

Based on dynamic triaxial test results of saturated soft clay, similarities of variations between accumulated pore water pressure and accumulated deformation were analyzed. The Parr＇s equation on accumulated deformation was modified to create an attenuation-type curve model on accumulated pore water pressure in saturated normal consolidation clay. In this model, dynamic strength was introduced and a new parameter called equivalent dynamic stress level was added. Besides, based on comparative analysis on variations between failure-type and attenuatiun-type curves, a failure-type curve model was created on accumulated pore water pressure in saturated normal consolidation clay. Two models can take cycle number, coupling of static and dynamic deviator stress, and consolidation way into consideration. The models are verified by test results. The correlation coefficients are more than 0.98 for optimization of test results based on the two models, and there is good agreement between the optimized and test curves, which shows that the two models are suitable to predict variations of accumulated pore water pressure under different loading cases and consolidation ways. In order to improve prediction accuracy, it is suggested that loading cases and consolidation ways should be consistent with in-situ conditions when dynamic triaxial tests are used to determine the constants in the models.

Research on Induction Normal Curvature and Critical Curves of Quasi－ellipsoidal Gear Drive with Inner－toroidal Teeth

Quasi-ellipsoidal gear drive is suitable for the precise flexible joint of robot,but some meshing problems of this transmission are rarely involved in the related papers.According to the two-parameter conjugate surface theory, this article studies on the induction normal curvature and critical curves, the method of analysis is efficient for not only the quasi-ellipsoidal gear drive but also the other types of spatial gear drive.

NORMAL CRITERIA FOR A FAMILY OF HOLOMORPHIC CURVES

In this paper,we extend the concept of holomorphic curves sharing hyperplanes and introduce definitions of restricted hyperplanes and partial shared hypersurfaces.Then,we prove several normal criteria of the family of holomorphic curves and holomorphic mappings that concern restricted hyperplanes and partial shared hypersurfaces.These results generalize the Montel-type normal criterion of holomorphic curves.

Shared Hyperplanes and Normal Families of Holomorphic Curves

In theorem LP [1], Liu proves the theorem when N = 2, but it can’t be ex-tended to the general case in his proof. So we consider the condition that the families of holomorphic curves share eleven hyperplanes, and we get the theorem 1.1.

Some Key Technologies of a New-type CNC Curve Grinding Machine

This paper presented a new-type CNC curve grinding machine, in order to conquer the disadvantages of conventional NC curve grinding machine and improve surface quality, dimensional accuracy and machining efficiency. The new-type grinder adopts some high and new technologies: ① the normal tracing device could make grinding wheel coincide with the normal direction of the machining points in work piece, and improve surface quality and dimensional accuracy; ② the digital image on-line recognition system could monitor machining process and compensate wheel wear in real time; ③ linear motor drive mechanism could realize the exact adjustment of the grinding head digitally and increase the machining efficiency. The math models of normal tracing and circular tolerance zone were presented. The experimental results show that the new-type CNC curve grinding machine equipped with the three devices mentioned above is easy to realize the precision grinding of any complex curve, and improve surface quality, dimensional accuracy and machining efficiency.

Distribution of driving trajectory of passenger car in highway horizontal curves

In this paper the track behavior of passenger car was studied. The vehicle driving trajectory and driving direction were defined, and a classification of the type of vehicle trajectories along the curves was developed. The statistical parameters of vehicle trajectory samples in free flow and their frequency curves and cumulative frequency curves were achieved, K-S test and chi-square test were used to test normal distribution and gamma distribution for collected sample data, and the probabili- ty density functions were given. At last, dispersion degree between vehicle trajectory random varia- ble and the characteristic value of cumulative frequency curve in each key cross section in curves was analyzied. The proposed conclusion can provide theoretical support for the reasonable optimization of widen curve, design of alignment and the management of counter flow conflicts.

Thin-Walled Tube Extension by Rigid Curved Punch

Computer model is developed for non-steady and steady-state process of thin-walled tube extension by the rigid punch with curved profile. Rigid-plastic membrane shell theory with quadratic yield criterion is used. Tube material normal anisotropy, work hardening, wall thickness variation and friction effects are considered. FORTRAN programs of the model predict distributions of the thickness, meridian stress, yield stress and pressure along curved generator of deformed tube and the tube extension force versus punch displacement relation. Model predictions are correlated with experimental data.

玛多M_(S)7.4地震前地电阻率变化

分别运用原始曲线分析法和归一化速率法分析2021-05-22玛多M_(S)7.4地震震中400 km范围内4个地电阻率台站的数据变化。结果表明:1)玛多地震前,4个地电阻率台站资料出现不同程度的异常变化,其中玛曲NW、金银滩EW、甘孜N10°E、拦隆口EW测道原始曲线变幅最明显,表现为小时值突跳变化、日均值加速变化和曲线转折变化、月均值破年变和保留年变形态的趋势变化;2)玛曲NW、金银滩EW、甘孜N10°E、拦隆口EW归一化速率曲线在玛多地震前均出现超阈值现象,但各自归一化速率形态不同;3)综合分析认为,4个台站地电阻率资料异常变化与玛多M_(S)7.4地震的孕育及活动有关。

基于Manhattan距离的正态云模型相似性度量方法研究

综合考虑正态云的期望曲线与含熵期望曲线,提出了一种基于Manhattan距离的正态云相似性度量方法。首先,将不确定性语言信息转化为定量数值,分别计算群体云评价与最优云、最劣云之间的相似度,采用加权平均集成给出综合相似度,从而得到各方案的排序。最后,通过实例说明该方法的有效性。

运输类飞机实测突风谱编制方法研究

目的针对运输类飞机突风载荷谱编制需求,基于实测载荷数据和任务分析法原理,采用5×5谱编制方法,建立一种运输类飞机实测突风谱编制方法。方法首先依据任务分析确定飞机典型任务剖面和任务段,对实测载荷数据进行预处理和统计分析,获得突风增量过载超越数的分布参数。然后通过得到的平均突风增量过载累积超越数曲线,编制各任务段载荷谱,进而编制任务剖面谱,按任务剖面比例,对任务剖面谱进行随机排序,编制得到了突风增量过载飞-续-飞谱。最后给出了一个示例以详细阐明该编谱方法。结果该型运输机爬升任务段突风载荷谱相较其余任务段偏重。结论通过该方法编制的突风载荷谱能够较好地反映实测突风载荷数据特点,方法具备合理性和可行性。

基于高斯混合模型及EM算法的建筑工程数据预警治理方法

结合初期雨水调蓄大直径顶管工程的实际设计及施工经验,对软弱地层条件下长距离大直径平行双管曲线顶管在设计及施工过程中存在的重点难点问题进行总结,并对顶管过程中的顶力及管周摩阻力做了深入分析研究,有针对性地提出了相应的解决方案,使该顶管工程顺利贯通。建筑工程行业在现代社会中发挥着重要的经济和社会作用,然而,它也伴随着诸多风险和不确定性。为了有效地管理和预测这些风险,本文提出了一种基于高斯混合模型(GMM)和期望最大化(EM)算法的数据预警治理方法。该方法旨在通过对建筑工程数据的建模和分析,提前识别潜在的问题和风险,从而改善工程项目的管理和决策。

基于数理统计方法的水质总氮校准曲线残差值检验

(目的)探讨水质总氮校准曲线残差值的正态性、独立性、同方差性。(方法)一年内对不同浓度的硝酸盐氮标准使用液进行了6次测定,对测定结果进行校准曲线拟合,计算残差值。通过QQ图及Anderson—Darling(AD)法检验残差值的正态性;通过图示法及DW法检验残差值的独立性;通过残差图及等级相关系数法检验残差值的同方差性。结果表明,该曲线残差值满足正态性,不满足独立性和同方差性。(结论)使用普通最小二乘法对数据进行曲线拟合需建立在一系列假定条件上,因此实际工作中不能盲目默认相关假定条件成立,应将数理统计理论与化验检测实际相结合,保障曲线拟合的可靠性。

渐开线轮齿啮合相对滑动速度与接触力分析

在研究某些特定问题时,需要将齿轮啮合点的速度和受力这两个时变矢量建立联系。通过共轭曲线原理和齿轮啮合原理,从几何解析的角度对齿轮啮合点的速度和受力进行分析,逐步推导出这两个矢量的数学模型。

交变双轴加载下钛合金微动磨损的仿真及试验研究

微动磨损是导致机械连接结构失效的主要形式之一。目前大多数研究都在恒定法向接触载荷工况下开展。然而实际工程中,广泛存在着可变法向载荷和轴向载荷的多轴加载工况,导致目前恒定法向载荷下微动磨损的研究结果不能很好地解释多轴交变加载工况下的微动磨损行为。因此,以钛合金的微动磨损为例,进行了交变双轴加载下微动磨损的仿真分析和试验测试研究。首先,建立了受循环交变双轴加载作用下的微动磨损模型;然后,对不同法向载荷幅值、位移载荷幅值、双轴加载相位差下的微动磨损行为进行了仿真,并根据Q-P曲线分析方法对这些复杂微动情况下的微动磨损机制进行了讨论;最后,在双轴加载的微动磨损试验机上进行了双轴微动磨损试验,验证了该有限元模型磨损形貌的合理性。研究结果表明:交变法向载荷的磨损形貌不同于恒定法向载荷的磨损形貌,交变下法向载荷均值与恒定法向载荷保持不变,交变法向载荷下的磨损深度及宽度均大于恒定法向载荷下的磨损深度及宽度。位移幅值和相位差一定,随着法向载荷幅值的增大,磨损宽度和深度均增加,磨损形貌由“W”型转变为“W+V”型;法向载荷幅值和相位差一定,磨损宽度和深度均随位移幅值的增大而增大;法向载荷幅值和位移幅值一定,改变双轴加载相位差,0°相位差最大磨损深度出现在接触后缘,180°相位差最大磨损深度出现在接触前缘,90°和270°相位差的前、后缘磨损深度极大值接近。

一种基于Normal基椭圆曲线密码芯片的设计

文章设计了一款椭圆曲线密码芯片,实现了GF(2233)域上normal基椭圆曲线数字签名和认证,并支持椭圆曲线参数的用户配置。在VLSI的实现上,提出了一种新的可支持GF(2233)域和GF(p)域并行运算的normal基椭圆曲线VLSI架构。其架构解决了以往GF(p)域运算迟后于GF(2233)域运算的问题,从而提高了整个芯片的运算吞吐率。基于SMIC0.18!m最坏的工艺,综合后关键路径最大时延3.8ns,面积18mm2;考虑布局布线的影响,芯片的典型的情况下,每秒可实现8000次签名或4500次认证。

Parametric design strategy of a novel cylindrical negative Poisson's ratio jounce bumper for ideal uniaxial compression load-displacement curve

A cylindrical negative Poisson's ratio(CNPR) structure based on two-dimensional double-arrow negative Poisson's ratio(NPR)structure was introduced in this paper. The CNPR structure has excellent stiffness, damping and energy absorption performances,and can be applied as spring, damper and energy absorbing components. In this study, the CNPR structure was used as a jounce bumper in vehicle suspension, and the load-displacement curve of NPR jounce bumper was discussed. Moreover, the influences of structural parameters and materials on the load-displacement curve of NPR jounce bumper were specifically researched. It came to the conclusion that only the numbers of cells and layers impact the hardening displacement of NPR jounce bumper. And all parameters significantly affect the structure stiffness at different displacement periods. On the other hand, the load-displacement curve of NPR jounce bumper should be in an ideal region which is difficult to be achieved applying mathematical optimization method. Therefore, a parametric design strategy of NPR jounce bumper was proposed according to the parametric analysis results. The design strategy had two main steps: design of hardening displacement and design of stiffness. The analysis results proved that the proposed method is reliable and is also meaningful for relevant structure design problem.

The Behavior of Normality when Iteratively Finding the Normal to a Line in an _lpGeometry

The normal direction to the normal direction to a line in Minkowski geometries generally does not give the original line. We show that in lp geometries with p>1?repeatedly finding the normal line through the origin gives sequences of lines that monotonically approach specific lines of symmetry of the unit circle. Which lines of symmetry that are approached depends upon the value of p and the slope of the initial line.