泰安桃园梨小食心虫发生与危害规律

本文调查了山东泰安地区单植和混植桃园中梨小食心虫成虫发生动态及幼虫危害规律。结果表明:单植桃园中,梨小食心虫一年发生5代,具有世代重叠现象;老龄桃园与幼龄桃园折梢率分别为17.87%与14.80%,但差异不显著;老龄桃园中5、6和7月份折梢率分别为7.60%、10.60%和35.40%,幼龄桃园中3个月份折捎率分别为2.20%、9.80%和32.40%,均存在显著性差异;东、西、南、北4个方位折梢率无显著性差异,分别为老龄桃园17.67%、18.33%、15.67%和20.33%,幼龄桃园12.67%、16.67%、14.33%和18.33%。混植桃园中,梨小食心虫一年发生5代;3个月份折梢率差异显著,分别为5.80%、22.20%和32.00%;不同方位折梢率无显著性差异,4个方位分别为16.00%、22.00%、17.67%和26.33%;6、7月份虫果率分别为33.80%和38.20%,差异不显著;东、西、南、北4个方位虫果率分别为31.00%、43.00%、35.00%和39.00%,差异显著。

桃小食心虫滞育过程中5种代谢酶活力变化

为明确桃小食心虫越冬适应机制,室内利用试剂盒测定了不同滞育时间桃小食心虫滞育幼虫的海藻糖酶、山梨醇脱氢酶、己糖激酶、丙酮酸激酶和碱性磷酸酶的活力。结果表明,不同滞育时间桃小食心虫体内海藻糖酶、己糖激酶、丙酮酸激酶、碱性磷酸激酶活力差异显著,而山梨醇脱氢酶活力差异不显著。海藻糖酶活力在滞育初期最高,而后随着滞育时间的延长逐渐降低;己糖激酶活力在滞育初期较低,在滞育后期先迅速升高再迅速下降;丙酮酸激酶在滞育中期活力最高,而碱性磷酸激酶活力在滞育初期最高。这表明桃小食心虫在滞育过程中通过代谢酶的调节,提高其越冬期间的抗寒能力,保证顺利越冬。

张氏积分法在非线性动力分析中的应用

一个理想的积分法希望同时具有内隐式积分法的无条件稳定与外显式积分法的计算简单的优点,张氏积分法即是为了此目的而发展出来的积分法,虽然已有完整的理论推导与简单的数值验证,但其在实务上的应用仍有待进一步的探究。为了验证张氏积分法的实用性与优异的计算效率,特别将张氏积分法加入Open Sees分析软件中,并针对各式各样不同类型的结构系统来进行动态历时分析。除了张氏积分法以外,也利用等平均加速度积分法与Newmark外显式积分法来进行动态历时分析,并经由分析结果的比较,除了可以验证张氏积分法的数值特性之外,也可以证实张氏积分法能广泛地应用于线性及非线性动力分析。最后则利用每次动力分析所使用的CPU时间比较,来进一步证实此积分法的优异计算效率。

互联网保险产品开发问题研究

近年来,互联网保险快速发展,然而在开发互联网保险产品的效果并不好。因此,能够实现保险企业在互联网市场中站住脚跟的关键就是开发出符合独特的符合市场需求的优秀产品,结合互联网保险本质意义来开展互联网在保险业方面的作用、互联网保险开发理念及模式、开发互联网保险产品存在的问题以及互联网保险产品开发策略四个方面内容。

Analytical exploration of γ-function explicit method for pseudodynamic testing of nonlinear systems

It has been well studied that the γ-function explicit method can be effective in providing favorable numerical dissipation for linear elastic systems. However, its performance for nonlinear systems is unclear due to a lack of analytical evaluation techniques. Thus, a novel technique is proposed herein to evaluate its efficiency for application to nonlinear systems by introducing two parameters to describe the stiffness change. As a result, the numerical properties and error propagation characteristics of the γ-function explicit method for the pseudodynamic testing of a nonlinear system are analytically assessed. It is found that the upper stability limit decreases as the step degree of nonlinearity increases; and it increases as the current degree of nonlinearity increases. It is also shown that this integration method provides favorable numerical dissipation not only for linear elastic systems but also for nonlinear systems. Furthermore, error propagation analysis reveals that the numerical dissipation can effectively suppress the severe error propagation of high frequency modes while the low frequency responses are almost unaffected for both linear elastic and nonlinear systems.

Analytical investigations of seismic responses for reinforced concrete bridge columns subjected to strong near-fault ground motion

Strong near-fault ground motion, usually caused by the fault-rupture and characterized by a pulse-like velocity- wave form, often causes dramatic instantaneous seismic energy （Jadhav and Jangid 2006）. Some reinforced concrete （RC） bridge columns, even those built according to ductile design principles, were damaged in the 1999 Chi-Chi earthquake. Thus, it is very important to evaluate the seismic response of a RC bridge column to improve its seismic design and prevent future damage. Nonlinear time history analysis using step-by-step integration is capable of tracing the dynamic response of a structure during the entire vibration period and is able to accommodate the pulsing wave form. However, the accuracy of the numerical results is very sensitive to the modeling of the nonlinear load-deformation relationship of the structural member. FEMA 273 and ATC-40 provide the modeling parameters for structural nonlinear analyses of RC beams and RC columns. They use three parameters to define the plastic rotation angles and a residual strength ratio to describe the nonlinear load- deformation relationship of an RC member. Structural nonlinear analyses are performed based on these parameters. This method provides a convenient way to obtain the nonlinear seismic responses of RC structures. However, the accuracy of the numerical solutions might be further improved. For this purpose, results from a previous study on modeling of the static pushover analyses for RC bridge columns （Sung et al. 2005） is adopted for the nonlinear time history analysis presented herein to evaluate the structural responses excited by a near-fault ground motion. To ensure the reliability of this approach, the numerical results were compared to experimental results. The results confirm that the proposed approach is valid.

Investigations of nonlinear performances of implicit pseudodynamic algorithms

Although it has been shown that the implementation of the HHT-α method can result in improved error propagation properties in pseudodynamic testing if the equation of motion is used instead of the difference equation to evaluate the next step acceleration, this paper proves that this method might lead to instability when used to solve a nonlinear system. Its unconditional stability is verified only for linear elastic systems, while for nonlinear systems, instability occurs as the step degree of convergence is less than 1. It is worth noting that the step degree of convergence can frequently be less than 1 in pseudodynamic testing, since a convergent solution is achieved only when the step degree of convergence is close to 1 regardless of whether its value is greater or less than 1. Therefore, the application of this scheme to pseudodynamic testing should be prohibited, since the possibility of instability might incorrectly destroy a specimen. Consequently, the implementation of the HHT-α method by using the difference equation to determine the next step acceleration is recommended for use in pseudodynamic testing.

梨小食心虫滞育与非滞育幼虫过冷却能力与体内主要生化物质含量

梨小食心虫Grapholitha molesta(Busck)是我国北方果园中重要的果树害虫,现已成为泰安肥城桃园中为害最为严重的一种食心虫。本文主要测定了梨小食心虫滞育与非滞育幼虫的过冷却能力与体内主要生化物质的含量。研究结果表明;在26℃的温度条件下,滞育幼虫的过冷却点与结冰点均低于非滞育幼虫,但差异均不显著。滞育幼虫体内的含水量、糖原和蛋白质含量均极显著低于非滞育幼虫,但是滞育幼虫体内的总脂肪、甘油和海藻糖含量均极显著高于非滞育幼虫。研究结果说明,滞育幼虫在体内生理生化代谢做了调整,以应对不利环境条件的来临。

桃小食心虫危害对苹果果实蛋白质含量及防御酶活性的影响

为探明桃小食心虫取食危害对不同品种苹果果实蛋白质含量和防御酶活性的影响,田间条件下采用人工接虫和针刺模拟危害苹果果实,处理12 d后调查果实受害程度并测定蛋白质含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,分析了果实蛀孔数与可溶性蛋白质和防御性酶活性的关系。结果表明:人工接虫后,"嘎啦"的蛀孔数显著多于"乔纳金"和"金帅"。桃小食心虫危害后苹果果实蛋白质含量变化不大,均显著低于针刺模拟处理;SOD活性显著高于针刺模拟处理(P<0.05);POD活性都显著增加,"乔纳金"、"金帅"的变化显著大于"嘎啦";CAT活性都与对照相比无显著变化,均高于针刺模拟处理,CAT酶活性与苹果蛀孔数呈显著正相关。桃小食心虫危害可以诱导寄主产生一系列反应,蛋白质含量和应激防御酶活性均发生了变化,其中,防御性酶可能在苹果防御桃小食心虫危害中发挥着重要作用。