液压试验条件下椭圆封头的破坏原因分析

通过对椭圆封头应力状态进行分析,阐明了现行椭圆封头的常规设计方法存在的不妥之处,合理地解释了液压试验条件下椭圆封头赤道附近受到破坏的原因,并就解决此类问题提出了建议．     

The differential impact of types of app innovation on customer evaluation

Digital innovation literature seldom considers the effects of innovation from app developers’ perspective. Even when it does, the findings on the value of app innovation are mixed. Based on technological innovation and early-mover advantages literature, we delineate types of app innovation and their impacts on customer evaluations. Our empirical results indicate that adding new business functions to provide new categories of product or service offerings increases customer evaluations, whereas, adding new supporting service functionalities (SSFs) decreases customer evaluations. For followers that “imitate” innovations, the effect of adding SSFs on customer evaluations is negatively contingent on the quality of early-mover apps.     

All-optical temporal fractional order differentiator using an in-fiber ellipsoidal air-microcavity

An all-optical temporal fractional order differentiator with ultrabroad bandwidth (~1.6 THz) and extremely simple fabrication is proposed and experimentally demonstrated based on an in-fiber ellipsoidal air-microcavity. The ellipsoidal air-microcavity is fabricated by splicing a single mode fiber (SMF) and a photonic crystal fiber (PCF) together using a simple arc-discharging technology. By changing the arc-discharging times, the propagation loss can be adjusted and then the differentiation order is tuned. A nearly Gaussian-like optical pulse with 3 dB bandwidth of 8 nm is launched into the differentiator and a 0.65 order differentiation of the input pulse is achieved with a processing error of 2.55%.     

附不等式约束的病态问题求解研究

病态问题产生的原因是设计矩阵存在复共线关系,为了消除法方程奇异,我们必须附加先验信息。不等式约束是客观实际中普遍存在的一种约束,是先验信息的主要表达方式之一,因此本文提出了附不等式约束的病态问题和其求解方法。本文在Rao提出的椭球约束法的基础上导出了不等式约束条件和广义岭参数之间的转换关系,然后用传统的广义岭估计来求解附不等式约束的病态问题。该种求解思想真正实现了由附加先验信息来决定岭参数。最后用一个模拟的算例检验了本文方法的可行性。同时,算例表明:不等式约束条件越正确、越苛刻得到的结果越接近真值,精度也越高。     

Buckling of super ellipsoidal shells under uniform pressure

This paper is concerned with the elastic buckling of super ellipsoidal shells under external uniform pressure. The middle surface of a super ellipsoidal shell is defined by the following equation: (x/a)²ⁿ+(y/b)²ⁿ+(z/c)²ⁿ=1, where n is an integer varying from unity to infinity. It is clear from the equation that the range of shell shapes covered sphere (n=1, a=b=c) to cube () and ellipsoid (n=1) to cuboid (n=∞). By adopting a recently proposed solid shell element for the buckling analysis, the critical buckling pressures of thin to thick super ellipsoidal shells are obtained and tabulated for engineers. The shell element allows for the effect of transverse shear deformation which becomes significant in thick shells. Their buckling shapes are also examined. In addition, a simple approximate formula for predicting the critical buckling pressure of thick spherical shells is proposed.     

大跨椭球面圆形钢拱结构的强度及稳定性分析

九寨沟甘海子国际会议度假中心温泉泳浴中心为一平面尺寸150m×65m的椭球形壳体。为满足建筑设计简洁通透的要求,该工程采用了沿椭球面短轴方向布置圆形钢拱结构为主要承载构件、拱间沿长轴方向布置矩形钢管作为檩条的结构方案。圆形钢拱则采用了一种新颖的上部∏形截面、下部圆管截面构成的组合截面形式。本文介绍了该结构的结构选型,分别给出了单拱结构、整体结构的内力分析、线性特征根屈曲分析及几何非线性分析的分析结果。分析表明,在升温条件下壳体结构出现很大的薄膜压应力,结构的稳定承载能力急剧下降。本文提出通过在结构中部设置伸缩缝的方法调整壳体屈曲前的薄膜应力状态,释放部分温度应力,从而达到提高结构整体稳定性的目的。     

机构综合的超混沌相乘求解方法研究

超混沌是现代科学的主要成就之一,扩展超混沌的应用对现代科学的发展有重要意义。研究了超混沌相乘方法,首次提出了相乘超混沌求解非线性方程组新方法,并对机构综合进行了研究,给出了计算实例。该方法简单、实用,为实际机构的设计提供了多种选择方案,为机构学设计提供了全新的方法。     

计算机结构的发展与新技术探讨

计算机发展日新月异,从计算机的核心部件-微处理器,到计算机整体结构均在持续发展,性能在不断提高.本文介绍现代计算机中总线结构发展的特点,以及超频及超线程等新技术,为从事计算机理论研究提供参考.     

椭圆封头压制过程中易产生的各类缺陷分析

借鉴各制造厂的实际经验和压制工艺,对椭圆封头压制中易产生的各类缺陷进行了分析。     

改进的TSK型动态模糊神经网络在短期负荷预测中的应用(英文)

将改进的TSK型模糊神经网络(fuzzy neural network,FNN)应用于短期负荷预测。该FNN由椭圆基函数构成神经元的中心和宽度参数,并且具有以下特征:网络结构和参数可自动并同时进行调整,不需提前分割输入空间,也不需提前选择网络初始参数;模糊规则在学习过程中可动态增删,不需采用迭代算法即可快速生成。这种模糊规则可动态增删的模糊神经网络(growing and pruning fuzzy neural network,GPFNN)简单有效,可以降低网络的复杂性,加快网络的学习速度。使用EUNITE竞赛数据作测试数据对上述GPFNN方法进行测试,结果表明采用该方法进行短期负荷预测时可获得较高的准确率。