DEPENDENCE OF MODULUS OF ELASTICITY AND THERMAL CONDUCTIVITY ON REFERENCE TEMPERATURE IN GENERALIZED THERMOELASTICITY FOR AN INFINITE MATERIAL WITH A SPHERICAL CAVITY

The equations of generalized thermoelasticity with one relaxation time with variable modulus of elasticity and the thermal conductivity were used to solve a problem of an infinite material with a spherical cavity.The inner surface of the cavity was taken to be traction free and acted upon by a thermal shock to the surface. Laplace transforms techniques were used to obtain the solution by a direct approach.The inverse Laplace transforms was obtained numerically.The temperature,displacement and stress distributions are represented graphically.

A PRIORI ESTIMATE FOR MAXIMUM MODULUS OF GENERALIZED SOLUTIONS OF QUASI-LINEAR ELLIPTIC EQUATIONS

Let G he a hounded domain in E Consider the following quasi-linear elliptic equationAlthough the houndedness of generalized solutions of the equation is proved for very general structural conditions, it does not supply a priori estimate for maximum modulus of solutions. In this paper an estimate to the maximum modulus is made firstly for a special case of quasi-linear elliptic equations, i.e. the A and B satisfy the following structural conditions

ON A GENERALIZED MODULUS OF CONVEXITY AND UNIFORM NORMAL STRUCTURE

In this article, the authors study a generalized modulus of convexity, δ（α） （ε）. Certain related geometrical properties of this modulus are analyzed. Their main result is that Banach space X has uniform normal structure if there exists ε, 0 ≤e≤ 1, such that δ^（α）（1＋ε ） 〉 （1- α）ε.

Equivalence of <i>K</i>-Functionals and Modulus of Smoothness Generated by a Generalized Dunkl Operator on the Real Line

This paper is intended to establish the equivalence between K-functionals and modulus of smoothness tied to a Dunkl type operator on the real line.

On Wavelet Transform General Modulus Maxima Metric for Singularity Classification in Mammograms

Continuous wavelet transform is employed to detect singularities in 2-D signals by tracking modulus maxima along maxima lines and particularly applied to microcalcification detection in mammograms. The microcalcifications are modeled as smoothed positive impulse functions. Other target property detection can be performed by adjusting its mathematical model. In this application, the general modulus maximum and its scale of each singular point are detected and statistically analyzed locally in its neighborhood. The diagnosed microcalcification cluster results are compared with health tissue results, showing that general modulus maxima can serve as a suspicious spot detection tool with the detection performance no significantly sensitive to the breast tissue background properties. Performed fractal analysis of selected singularities supports the statistical findings. It is important to select the suitable computation parameters-thresholds of magnitude, argument and frequency range-in accordance to mathematical description of the target property as well as spatial and numerical resolution of the analyzed signal. The tests are performed on a set of images with empirically selected parameters for 200 μm/pixel spatial and 8 bits/pixel numerical resolution, appropriate for detection of the suspicious spots in a mammogram. The results show that the magnitude of a singularity general maximum can play a significant role in the detection of microcalcification, while zooming into a cluster in image finer spatial resolution both magnitude of general maximum and the spatial distribution of the selected set of singularities may lead to the breast abnormality characterization.

Blind adaptive constrained constant modulus algorithms based on unscented Kalman filter for beamforming

This work proposes constrained constant modulus unscented Kalman filter(CCM-UKF) algorithm and its low-complexity version called reduced-rank constrained constant modulus unscented Kalman filter(RR-CCM-UKF) algorithm for blind adaptive beamforming. In the generalized sidelobe canceller(GSC) structure, the proposed algorithms are devised according to the CCM criterion. Firstly, the cost function of the constrained optimization problem is transformed to suit the Kalman filter-style state space model. Then, the optimum weight vector of the beamformer can be estimated by using the recursive formulas of UKF. In addition, the a priori parameters of UKF(system and measurement noises) are processed adaptively in the implementation. Simulation results demonstrate that the proposed algorithms outperform the existing methods in terms of convergence speeds, output signal-tointerference-plus-noise ratios(SINRs), mean-square deviations(MSDs) and robustness against steering mismatch.

A New Thiele＇s Modulus for the Monod Biofilm Model

A new Thiele＇s modulus, φF, was developed to provide a gradual transition between zero and the first order of kinetics, and to accurately calculate the mass transfer flux and the effectiveness factor for the Monod biofilm. Values of the effectiveness factor, calculated using the new Thiele＇s modulus, were compared with those obtained from numerical solutions and from other published moduli and empirical formulae. The comparison indi- cated that the new Thiele＇s modulus was the best modulus for the Monod biofilm model. In addition, another Thiele＇s modulus, φG, was developed for a Monod biofilm, covered with an external water layer. The overall effectiveness factor can also be calculated by using both moduli φF and φG. The criteria that were proposed for identifica- tion were based on the values of φF and φG, the limiting processes for biomass growth, and substrate conversion. Developed from φF, a new parameter ψ was related uniquely to such features as the depth and shallowness of the generalized substrate concentration profiles inside a Monod biofilm. Criteria were developed to identify the types of concentration distribution inside a Monod biofilm. These methods were used to estimate the substrate flux and the concentration distribution of the biofilms defined in the first benchmark problem （BM1）, by a task group of the International Water Association on Biofilm Modeling.

ON THE GENERALIZED ORDER OF DIRICHLET SERIES

By the method of Knopp-Kojima, the generalized order of Dirichlet series is studied and some interesting relations on the maximum modulus, the maximum term and the coefficients of entire function defined by Dirichlet series of slow growth are obtained, which briefly extends some results of paper [1].

大学物理实验课程的通识教育探究——以“拉伸法测定弹性材料的杨氏模量”为例

“大学物理实验”课程是理工科学生较早接触的实验操作类课程,涵盖了力学、热学、电学、磁学、光学等多个分支领域。华东师范大学大学物理实验教学团队在实验教学中坚持将学科知识和通识元素有机融合,将综合育人的理念贯穿始终。本文以“拉伸法测定弹性材料的杨氏模量”为例,从“实验背景、目标要点、通识融入、案例挖掘”入手,探讨如何在大学物理实验教学过程中实施通识教育,以期兼顾“授业解惑和传道育人”,践行立德树人的教育初心。

农田排涝模数计算方法比较研究

【目的】探究径流深与排涝模数计算方法的差异性,确定合理的农田排水工程规模。【方法】基于历史降水资料、排涝泵站运行数据和土地利用类型数据,计算三江平原绥滨县蜿蜒河涝区实际径流深(RO),采用综合加权法和SCS-CN方法计算了涝区理论径流深(R_(GM)、R_(SCS)),在此基础上,用经验公式法和平均排除法计算区域排涝模数(Q_(E)、Q_(A)),比较分析径流深与排涝模数计算方法的适用性。【结果】在同一年份同一重现期下,降水历时越长实际径流深越大;同一降水历时同一重现期下,实际径流深随着年份的推移而减小;实际径流深和排涝模数与理论径流深和排涝模数存在偏差。大降水情况时,R_(GM)>R_(SCS)>R_(O);小降水情况时,R_(SCS)<R_(GM)<R_(O)。根据实际和理论径流深计算出的排涝模数规律与径流深规律相同;大降水情况下,1日降水历时Q_(A)>Q_(E);3日降水历时Q_(A)<Q_(E)。【结论】考虑了前期土壤状况的SCS-CN方法更适宜平原涝区径流深计算,但需要选择适宜的CN值。引入迟缓-槽蓄系数的平均排除法更能反映出大流域的调蓄作用。在经济发展水平较低且经济增速缓慢的地区,对于大面积滞蓄条件较好的平原涝区选择更长的排涝历时时,采用加入槽蓄-迟缓系数的平均排除法计算排涝模数更适宜。

盐酸特比萘芬乳膏流变学性质的研究

目的对盐酸特比萘芬乳膏进行流变学性质的研究,为该产品的一致性评价提供研究依据。方法采用高级旋转流变仪测定盐酸特比萘芬乳膏稳态和非稳态流变学参数,对参比制剂与6个仿制制剂进行流变曲线、屈服应力、黏度、线性黏弹性、蠕变回复等性质的对比研究。结果盐酸特比萘芬乳膏参比制剂及仿制制剂均为假塑性非牛顿流体;屈服应力试验中,3家仿制制剂与参比制剂大小相当;3家仿制制剂的线性黏弹区范围与参比制剂一致,在0.01%~1%范围内,两者弹性模量均大于黏性模量,均为黏弹性体;蠕变回复曲线可知4家仿制制剂与参比制剂的蠕变行为相当。结论试验测定的6个盐酸特比萘芬乳膏中,大部分仿制制剂与参比制剂的流变学性质基本一致。

钢筋混凝土拱承载力分析的齐次广义屈服函数

为了解决弹性模量调整法应用于钢筋混凝土(RC)结构的难题,建立了矩形截面RC偏压构件的通用齐次广义屈服函数。充分考虑RC偏压构件的破坏机理,并利用二次函数建立了矩形截面RC构件的分段光滑压弯承载力相关方程。通过回归分析建立分区表达的截面特征函数,以综合考虑钢筋混凝土偏压构件的截面几何和材料性能对承载力的影响,在此基础上采用分数指数幂的一阶多项式建立矩形截面RC偏压构件的齐次广义屈服函数。利用单元承载比定义高承载单元的自适应识别准则,通过有策略地缩减高承载单元的弹性模量模拟RC拱结构高应力区域的刚度退化,并根据线弹性迭代分析确定RC拱的极限承载力,据此提出了RC结构承载力分析的弹性模量缩减法。通过与模型试验及增量非线性有限元法对比分析,验证了该文方法具有较高的计算精度与计算效率。

基于成形磨削的大模数风电齿轮磨削极限位置的获取方法

作为较有潜力的能源之一,风力发电的应用越来越广泛。作为风力发电系统的关键核心装备,齿轮箱质量的好坏直接决定了整套风力发电装备的使役性能。作为齿轮箱的典型零件,齿轮的表面精度是决定齿轮箱质量的关键因素之一。风电齿轮一般采用滚齿作为粗加工与成形磨齿作为精加工的方式获得。成形磨削过程中,磨削极限位置的获取对于了解磨削过程、优化磨削参数以及消除加工缺陷至关重要。提出了一种获取极限磨削位置的方法。根据滚齿加工展成法的基本原理,获取滚齿形成的齿形曲线;以成形磨削为基础,在不同进给余量的前提下,建立极限磨削位置的数学模型,并利用合适的数值迭代算法获取了该位置;以某典型风电斜齿轮为例,说明了所提方法的正确性和有效性。

面向多曲线的通用高性能ECC处理器设计

该文针对广泛应用的TLS1.3协议,提出了一种高性能的椭圆曲线密码处理器.该处理器支持TLS1.3协议中定义的两类素数域椭圆曲线的通用模数.通过对高基蒙哥马利算法的改进,提出了一种支持521 bit及以下位宽的模乘运算单元,并提出了一种双模乘单元并行结构的标量乘法器.基于该结构在两类椭圆曲线下设计了雅阁比坐标系下并行的点运算时序排布,使模乘单元的利用率在不同点运算情况下达到100%,95.4%和86.5%.与现有设计相比,本文中标量乘法运算消耗的周期更少,运算单元利用率更高,在相似的时间面积乘积前提下,具有更强的通用性和可配置性的优势.在TSMC 55 nm CMOS工艺下达到454 MHz的时钟频率,等效逻辑门数851k,Secp256r1曲线的标量乘运算速度为31230 times/s.

基于AMEsim柱塞压力发生器液体压力传递特性研究

为得到压力发生器柱塞位移与输出压力的关系、实现对输出压力的精准控制,对压力发生系统进行数学建模。以AMEsim有效体积弹性模量模型为基础,建立新的油液含气量插值多项式函数,解决了在饱和蒸汽压力与空气分离压力中间位置的导数突变问题。仿真分析了空气含量与温度对系统压力传递过程的影响,结果表明系统受空气含量影响较大,受温度影响较小,且空气含量每增加0.5%,系统响应时间与稳定时间会滞后0.7 s左右,柱塞用于压缩油液气泡的位移会增加20 mm左右。对比仿真与实测结果知,压力发生系统受空气含量影响,升压段耗时与响应误差总体上均大于降压段,保压5 s时各检定点的压力波动均在±0.03 MPa范围内。

土的变形模量和压缩模量

土的变形模量和压缩模量对岩土工程设计具有非常重要的意义。对这两个参数,很多学者从理论和实践的角度进行了大量的探索,但至今仍无法理清两者之间到底存在怎样的对应关系。本文提出土的变形模量可以采用与固结试验类似的方法获得,且其与广义虎克定律的理论关系较为对应。文中对由载荷试验所得变形模量在理论与实践方面存在差异的原因进行了分析,并提出应对该参数进行重新定义的观点。

关于黏弹性材料的广义Maxwell模型

采用流变力学分析黏弹性材料的流变特性时,常要用到广义Maxwell模型表达的应力松弛模量．而从试验中获得的应力松弛模量,其表达式常为Kohlrausch—William—Watts function(KWW函数)形式．通过把 KWW函数和广义Maxwell模型的拟合问题转化为两矩阵相等的求解问题后,又把两矩阵的相等等价于两矩阵差值向量的一阶范数为无穷小的问题,并通过引入广义逆矩阵,求得两矩阵差值向量的一阶范数的最小值,最后以一阶范数的最小值为目标函数,松弛时间为约束条件,利用单纯形法对两矩阵差值向量的一阶范数的最小值优化,从而提出了一种针对黏弹材料的KWW函数与广义Maxwell模型转换的计算方法．借助于 MATLAB软件,实现了对黏弹材料的广义Maxwell模型的拟合．

循环荷载作用下花岗岩动力特性试验研究

通过在RMT–150B多功能全自动刚性岩石伺服试验机对取自海南昌江核电厂一期工程常规岛的微风化和中风化黑云母花岗岩进行单轴压缩变形试验和循环加卸载试验,研究花岗岩动应力–动应变曲线滞回特性和动弹性模量与阻尼比同弹性模量之间的规律,并利用广义开尔文流变模型来描述循环荷载下花岗岩的滞回曲线和能量损耗情况。研究结果表明:花岗岩在循环荷载作用下的加卸应力–应变曲线形成滞回环,随着循环数的增加,滞回环向轴向应变增大的方向移动,且越来越密集;花岗岩的滞回环面积和最大弹性应变能都随弹性模量的增加而减少,而动弹性模量则相反,阻尼比先随弹性模量的增大而增大,达到一峰值后,随弹性模量的增大而减少;广义开尔文模型可以较好地描述花岗岩的滞回曲线和能量损耗情况。研究成果对海南昌江核电厂地基的地震反应分析和场地安全性评价有着重要的参考意义。

基于Birgé-Massart阈值的烟气发电机组状态特征弱信息提取方法

烟气发电机组是石油化工行业中的一种高速旋转大型机械,用于将催化裂化再生烟气中具有的能量转变成机械能。为保证机组安全、稳定运行而进行的运行状态监测,需解决机组在大量背景噪声下状态特征弱信息提取的问题。为此研究基于Birgé-Massart惩罚函数策略获取阈值的信号小波变换模极大值抑制噪声算法。由Birgé-Massart惩罚函数策略获取阈值,在小波变换不同分解尺度上构建不同的模极大值点邻域来影响模极大值点搜索过程,获得小波分解各尺度上合适的模极大值点序列,凸显状态特征信息,利用Mallat的交错投影法重构信号。为验证该算法的有效性,将该算法与Rigrsure、Sqtwolog、Heursure、Minimaxi四种阈值抑噪方法进行比较,结果表明该算法具有更好的信噪比和方均根误差。应用该算法对现场采集的振动信号进行状态特征弱信息提取处理,结果表明处理后的信号在保留突变点的同时,具有良好的光滑性,可以用来进行烟气发电机组状态特征信息的提取。

基于DMA方法的浇注式沥青胶浆高温性能及评价指标

为了研究浇注式沥青胶浆的高温性能及评价指标,采用动态力学分析(DMA)方法,通过动态剪切流变试验,探讨了不同温度、沥青种类、粉胶比对浇注式沥青胶浆高温性能的影响.分析了广义剪切模量与浇注式沥青混合料高温变形之间的相关性,探讨了该指标作为浇注式胶浆高温性能评价指标的适用性,并以车辙深度为控制标准,对广义剪切模量以及60℃条件下的贯入度提出了建议值.结果表明:浇注式沥青胶浆复数剪切模量和相位角受温度、沥青种类、粉胶比因素影响明显;广义剪切模量与混合料永久变形呈良好的线性关系,能作为一种合适的劲度指标评价浇注式沥青胶浆的高温稳定性;60℃条件下,浇注式沥青混合料贯入度指标建议值不大于3.29 mm.