Data requirements for neutron activation: Part I: Cross sections

Existing neutron cross section libraries such as EAF-2003 contain a large number of reactions. Of these only a small proportion are significant in the production of the nuclides that dominate activation quantities such as activity or γ-dose rate at various decay times. These reactions were identified in a recent extensive set of calculations on all the elements and reported in the ‘Activation Handbook’. These 1340 reactions are considered here and the set of reactions with no differential or integral data are listed and prioritised. A set of 339 reactions with very limited possibility of measurement are given; these require further study by theoretical calculations. A set of 100 reactions with either discrepant or no data, that might be measurable are listed and are recommended to be the subject of future experimental work.     

浅谈胶条接头与模具设计

简要地介绍了橡胶条常见接头工艺方法、应用特点及模具结构与设计方法。     

Analysis of frictional energy dissipation on an annular surface with harmonic loading

Metallic mating surfaces in structural joints offer a good source of frictional energy dissipation resulting in a damped dynamic structural response. This paper reports the results of experiments where the energy dissipation per cycle occurring at a preloaded flat metallic annular interface subjected to cyclic tangential forces is measured. The effects of certain pertinent joint variables on this frictional energy dissipation are investigated by the application of Response Surface Methodology. A central composite rotatable design was utilized for developing empirical expressions for energy loss. The methodology presented suggests a useful technique for tribological research.     

The use of the stable isotope 44Ca in studies of calcium incorporation into dentin

The incorporation into rat incisor dentin of two calcium isotopes, the stable ⁴⁴Ca and the radioactive ⁴⁵Ca, was studied using secondary ion mass spectrometry (SIMS) stepscanning and imaging, and autoradiography, respectively. The results demonstrated a time-dependent incorporation of the calcium isotopes into the mineral phase of dentin. With the SIMS step-scanning, detecting ⁴⁴Ca, the ion yield was high in the odontoblasts 2 min after intravenous injection. After 10 min a marked increase in signal intensity was found at the dentin mineralization front. This result was consistent with those obtained by ⁴⁵Ca autoradiography; a peak of incorporation occurred 10 min after injection of the isotope. Likewise, localization of ⁴⁴Ca to the mineralization front could be demonstrated 10 min after injection by SIMS imaging. In images obtained at earlier intervals, no such increase in ion yield could be detected. The results show that the nonradioactive, stable isotope ⁴⁴Ca can be used as a marker for biomineralization in a similar way to radioactive ⁴⁵Ca.     

布尔函数的对偶性和线性点

本文主要讨论了部分自对偶和部分反自对偶函数、部分线性函数以及具有线性点的函数的性质。     

煤气管道膨胀节腐蚀和在线包焊技术应用

简单分析了高炉煤气中Cl元素的存在对不锈钢膨胀节的应力腐蚀问题和防止途径，作为一种临时性的防范措施，简要介绍了煤气膨胀节包焊实施步骤和措施。     

铰接顶梁接头模具的热处理

叙述了热锻模的工作条件及材料分析 ,对铰接顶梁接头模具的热处理工艺作了探讨。     

三峡工程左厂房坝导墙抗震计算分析

 用反应谱理论对三峡左厂房坝导墙3种典型设计断面型式进行了抗震计算分析比较，得出了其自振特性及地震动位移、动应力响应。对选定的设计断面型式Ⅲ进行了抗拉应力强度安全性评价。     

智能化红外焊缝检测仪的实时信号自相关分析

详细介绍了在改进红外焊缝检测仪的过程中实时信号的一种抗干扰方法－－自相关方法。重点离自相关方法的数学模型，软件框图及设计思想，并给出了实验结果。     

差分扩频技术在移动水声通信中的应用

提出了基于差分相干解调法的DS/BDPSK水声通信技术,在接收端采用差分相干解调的方法,解决了在水声通信中载波估计较难的问题,可克服传输过程中由于载波漂移产生的频率和相位误差.通过计算机仿真研究、湖试试验,验证了该系统在复杂的水声信道中具有较强的抗多径能力、抗多普勒能力,能实现低误码率通信,具有较好的有效性和鲁棒性.