金属橡胶材料阻尼测试的一个新方法

金属橡胶材料是一种新型减振缓冲材料。本文提出了一个金属橡胶材料阻尼性能的测试方法。基于粘弹性阻尼耗能的基本原理,在给定应变激励函数的条件下,构造了一个等效应力响应函数,由滞环面积相等建立了一组包含实测应力响应和等效应力响应的等效耗能方程,将应变激励函数离散得到了损耗因子的计算表达式,由此可以通过实测应力方便地计算出损耗因子。该方法不仅便于对大阻尼材料的阻尼进行测试,而且具有精度高的优点。依据这一方法对金属橡胶材料进行了测试,测试结果表明我们开发的金属橡胶材料有很好的阻尼减振性能。     

Phase Behavior of Methane-Pentane Mixture in Bulk and in Porous Media

The adiabatic calorimetry method is used to measure the isochoric heat capacity and the dew-bubble curves for the methane-normal pentane mixtures in bulk for three different mixture compositions of n-pentane. The near-critical behavior of the mixture heat capacity indicates that at low n-pentane concentrations, this system is close to the special point of the critical locus. The effect of porous medium has been investigated for one of the mixtures studied in bulk. It has been shown that in porous medium the essential shift of the dew-bubble curve takes place. In our opinion this shift is caused by the formation of wetting film on the surface of porous medium. The estimation of film thickness resulting from the data obtained yields the value 7–8 nm.     

中柱失效工况下单层组合框架受力理论分析

基于已有试验，本文提出了轴向弹簧和转动弹簧约束的组合框架简化计算模型，推导了在集中荷载作用下刚性、半刚性连接平面组合梁双跨钢框架移除中柱后的荷载-跨中挠度曲线计算公式，考虑了压拱效应和连接刚度的影响，将公式计算结果与试验结果进行对比证明了推导过程和计算公式的可靠性．在对比结果的基础上，根据已有试验和模拟结果对已有悬索阶段的计算公式进行修正，修正后的公式与试验结果吻合较好．     

PBX颗粒力学性质对其撞击感度影响的初步研究

利用自行研制的应力测试系统研究了在机械撞击作用下粉状塑料粘结炸药(PBX)的表现。结果表明,由不同的聚氨酯(PU)溶液处理黑索今(RDX)得到的混和炸药PU-RDX,在机械撞击作用下给出的应力-时间曲线是多样的。而且PU-RDX的机械撞击感度随出现第二个应力峰的时间比(指不同的PU-RDX第二应力峰出现时间和仪器在空打时相应时间比)的增大,有下降的趋势。该时间比在一定程度上代表了粉状PU-RDX的塑性。研究在机械撞击作用下PBX的应力-时间特性有助于理解钝感炸药的机理、改进有关的工艺。     

光生物节律因子计算模型的研究

通过实验测量额头温度拟合光生物节律因子-额温差曲线,对现有评价光生物效应作用大小的BioEq模型和CLA模型的计算结果进行分析比较.利用不同图片LCD屏幕的光谱计算节律因子,发现两种模型对于绿色波段的光抑制较强,而对红色波段的光则与实际不相符.通过对九种不同颜色的LED光源测试额头温度,比较模型计算结果与实际光生物效应的作用,发现光生物节律因子与生理体征变化线性递增,其中对BioEq模型的直线拟合相关度达到0.95.     

Sulfur removal from bauxite water slurry (BWS) electrolysis intensified by ultrasonic

Effects of ultrasonic on desulfurization ratio from bauxite water slurry (BWS) electrolysis in NaOH solution were examined under constant current. The results indicated that ultrasonic improved the desulfurization ratio at high temperatures because of the diffusion and transfer of oxygen gas in electrolyte. However, due to the increase in oxygen gas emission, ultrasonic could not improve the desulfurization ratio obviously at low temperatures. Additionally, the particle size of bauxite became fine in the presence of ultrasonic, indicating that the mass transfer of FeS₂ phase was improved. According to the polarization curves, the current density increased in the presence of ultrasonic, indicating that the mass transfer of liquid phase was improved. The apparent activation energy (AAE) of electrode reaction revealed that ultrasonic did not change the pathway of water electrolysis. However, ultrasonic changed the pathway of BWS electrolysis, converting indirect oxidation into direct oxidation. The AAE of BWS electrolysis in the presence of ultrasonic was higher than that in the absence of ultrasonic. And the low AAEs (less than 20 kJ/mol) clearly indicated the diffusion control during BWS electrolysis reaction.     

Sequences of harmonic maps in the 3‐sphere

We define two transforms of non‐conformal harmonic maps from a surface into the 3‐sphere. With these transforms one can construct, from one such harmonic map, a sequence of harmonic maps. We show that there is a correspondence between harmonic maps into the 3‐sphere, H‐surfaces in Euclidean 3‐space and almost complex surfaces in the nearly Kähler manifold . As a consequence we can construct sequences of H‐surfaces and almost complex surfaces.     

关于具有二次相关性收获率的捕食与被捕食系统极限环的存在性分析

讨论了一类两种群具有二次相关性收获率的捕食与被捕食系统,利用常微分定性方法和分支理论,得到了系统平衡点处的性态和极限环的存在性条件,并用Matlab软件对其进行数值模拟,推广了相关文献中两种群捕食模型定性分析的相应结论.     

平板折叠桌的设计模型

根据折叠桌的运动特征,选取折叠桌的四分之一为研究对象,建立任意角度下桌脚点的运动变化模型。考虑到产品稳固性、加工便利性和节约用材三方面对加工参数的影响,对折叠桌进行受力分析,得到多目标组合优化模型,用以确定出折叠桌的最优设计参数。针对用户提出的桌面形状要求,建立桌脚曲线的参数方程。作为模型推广,以椭圆状折叠桌为例,运用Matlab画出了桌脚边缘线在折叠过程中的动态变化示意图。同时,又深入研究Robert van Embricqs的滑动折叠桌,建立了新的桌脚曲线参数方程。最后,运用Matlab对多种形状折叠桌进行仿真,编写多目标优化算法,得出了最优加工参数,并进行了算法描述。     

MilCAN总线同步及调度配置方法

MilCAN作为一种以陆军地面武器平台应用为目标的CAN高层协议,核心是通过时序控制保证总线通信的实时性和确定性;为了增强MilCAN总线通信时序控制,提出一种新的MilCAN总线同步和调度配置方法;采用STM32微控制器对MilCAN总线主控节点进行设计,将总线同步和总线调度配置任务集成至专用的主控节点进行,同时开展了总线通信测试;测试结果表明：以该方法设计的MilCAN总线主控节点可有效完成同步和总线调度配置任务,同步精度较高,性能稳定可靠。