摘要：This paper proposes a theoretical method using finite element analysis(FEA) to calculate the plastic collapse loads of pressure vessels under internal pressure,and compares the analytical methods according to three criteria stated in the ASME Boiler Pressure Vessel Code. First,a finite element technique using the arc-length algorithm and the restart analysis is developed to conduct the plastic collapse analysis of vessels,which includes the material and geometry non-linear properties of vessels. Second,as the mechanical properties of vessels are assumed to be elastic-perfectly plastic,the limit load analysis is performed by em-ploying the Newton-Raphson algorithm,while the limit pressure of vessels is obtained by the twice-elastic-slope method and the tangent intersection method respectively to avoid excessive deformation. Finally,the elastic stress analysis under working pressure is conducted and the stress strength of vessels is checked by sorting the stress results. The results are compared with those obtained by experiments and other existing models. This work provides a reference for the selection of the failure criteria and the calculation of the plastic collapse load.

摘要：Cold-stretched pressure vessels from austenitic stainless steels （ASS） are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an important concern in these pressure vessels, which are subjected to alternative loads. Even though several codes and standards have guidelines on these pressure vessels, there are no relevant design methods on fatigue failure.

摘要：This paper discusses the design and implementation of a low cost multi-sensor integrated attitude determination system for small unmanned aerial vehicles( UAVs),which uses strapdown inertial navigation system( SINS) based on micro electromechanical system( MEMS) inertial sensors,commercial GPS receiver,and 3-axis ***-SINS initial attitude determination cannot be well performed for the reason that the MEMS inertial sensors biases are time-varying and poor repeatability,therefore in this paper the magnetometer and inclinometer are used to assist the MEMS-SINS initial attitude determination and MEMS inertial sensors field ***,the attitude determination algorithms are presented to estimate the full attitude during GPS signal outage and non-accelerating ***,the attitude information estimation results are compared with the reference of the non-magnetic marble platform and 3-axis *** the attitude estimation precision satisfies the requirement of attitude measurement for small UAVs during GPS signal outage and ***,the small UAV autonomous flight test results show that the low cost and real-time attitude determination system can yield continuous,reliable and effective attitude information for small UAVs.

摘要：安全与经济并重、安全与资源节约并重已成为压力容器发展的重要理念,轻型化是这一理念的具体体现。从提高材料强度、降低安全系数、选用更高屈服强度、采用应变强化技术、运用分析设计方法以及优化压力容器结构等方面阐述压力容器的轻型化发展趋势。

摘要：设计合成了3个氨基苯基类中氮茚化合物，研究了其在不同pH值的缓冲溶液中的荧光强度变化．结果表明，在pH=2．1～4．2之间，该类化合物具有荧光敏感性．化合物3a和3b可以作为良好的质子控制的荧光开关器件信号分子．

摘要：为合理确定应变强化工艺参数,试验研究了材料化学成分、板材厚度及应变速率等因素对奥氏体不锈钢的强度、塑性等力学性能的影响规律。研究发现,对于应变强化用奥氏体不锈钢,应确保Ni、Mn等奥氏体稳定化元素的含量。应变强化奥氏体不锈钢低温容器的设计制造应充分考虑冷热轧制工艺导致的不同厚度板材力学性能差异。拉伸应变速率越低,强化压力下的形变量越大,应变速率对奥氏体不锈钢力学性能的影响随形变量的增加而逐渐减弱。

摘要：为实现对金属粉末压坯烧结过程的实时观测,从而验证现有的相关理论,本文利用同步辐射CT(SR-CT)技术,对铝压制陶瓷坯体的固相烧结过程进行实时投影成像;应用滤波反投影算法和数字图像处理技术,得到了陶瓷坯体在整个固相烧结过程中内部微结构演化的三维重建图像,实现了对铝压制陶瓷坯体整个固相烧结过程的无损原位观测,得到了样品由烧结中期进入烧结后期的完整的演化过程图像。通过重建图像,清晰观测了样品的固相烧结过程:在烧结前、中期(烧结时间t<180min、温度T<600℃),烧结颈形成并随烧结时间生长;由烧结中期开始进入后期时(烧结时间t≥180min、温度T≥600℃),样品内部结构演化加剧,气孔由相互连通演化为相互孤立并球化。进一步在实验图像的基础上分析了二面角等烧结特征的变化情况,得到烧结颈尺寸与时间对数有较好的线性关系,并可根据曲线分辨中期、后期。统计了样品在不同烧结时间的孔隙率,得到了孔隙率随烧结时间和烧结时间对数的变化曲线;分析了样品在不同烧结阶段的致密化特点,得到了烧结中期孔隙率和时间对数的线性关系。实验结果验证了现有的烧结理论,并为进一步完善烧结理论以及建立扩散和本构模型提供了高质量的实验数据。

摘要：实验室温度控制系统要求精度高,并且具有非线性、大惯性及数学模型难建立等特性,这使得用常规PID控制器以及一般模糊控制器无法很好地满足系统要求,而本文在一般模糊控制器的基础上,融合神经网络技术,设计出模糊神经网络控制器,它既有模糊控制鲁棒性好、动态响应好、上升时间快、超调小的优点,又具有神经网络的在线自学习能力,可以实现温度的智能控制,在实际应用中取得良好的效果。

摘要：GB 150—2011中采用的是弹性失效准则,规定对设计压力p≤0.4[σ]t的内压圆筒厚度按中径公式进行设计。JB 4732—1995中规定对设计压力p≤0.4[σ]t的内压圆筒厚度按中径公式进行设计,设计压力p>0.4[σ]t时按Tresca全屈服压力进行设计。比较研究表明:基于弹性失效准则时,中径公式算出的厚度最薄;基于塑性失效准则时,中径公式算出的厚度最厚;当径比较小时,按Tresca全屈服压力和中径公式算出的内压圆筒厚度相差很小,在工程设计中,可以统一采用Tresca全屈服压力计算内压圆筒壁厚。

摘要：介绍了一款饭店桌面无线点菜系统,硬件上采用AT89C52单片机作为系统的控制核心,应用键盘、数据收发、汉字显示、存储的扩展、看门狗硬件复位等技术,给出了其硬件电路原理、软件编程思路及应用程序,最后对设计中应注意的器件选择问题进行了说明。