用PSD构成全方位高准确度数字水平仪

本文利用连续型光电位置探测器ＰＳＤ（Ｐｏｓｉｔｉｏｎ Ｓｅｎｓｉｔｉｖｅ Ｄｅｔｅｃｔｏｒ）作为传感器,以重力方向作为竖直基准,构成了一种全方位高准确度水平仪,能实时地给出待测平面的倾斜角度和倾斜方位,具有量程可调结构紧凑、应用范围广等特点。     

Algebraic iterative algorithm for deflection tomography and its application to density flow fields in a hypersonic wind tunnel

A novel algebraic iterative algorithm based on deflection tomography is presented. This algorithm is derived from the essentials of deflection tomography with a linear expansion of the local basis functions. By use of this algorithm the tomographic problem is finally reduced to the solution of a set of linear equations. The algorithm is demonstrated by mapping a three-peak Gaussian simulative temperature field. Compared with reconstruction results obtained by other traditional deflection algorithms, its reconstruction results provide a significant improvement in reconstruction accuracy, especially in cases with noisy data added. In the density diagnosis of a hypersonic wind tunnel, this algorithm is adopted to reconstruct density distributions of an axial symmetry flow field. One cross section of the reconstruction results is selected to be compared with the inverse Abel transform algorithm. Results show that the novel algorithm can achieve an accuracy equivalent to the inverse Abel transform algorithm. However, the novel algorithm is more versatile because it is applicable to arbitrary kinds of distribution.     

考虑冷却措施的高混凝土坝施工过程温度场分析研究

为充分开发利用我国蕴藏的丰富水能,一批高混凝土坝正在规划建设之中.在高混凝土坝施工过程中,由于温度处理不当而导致坝体开裂甚至危及坝体安全的事例较为多见,温度控制问题已成为影响坝体施工速度和坝体安全的关键因素.埋设冷却水管是混凝土坝人工冷却的一个有效手段,可以实现削减初期温度峰值、减少混凝土温度降至稳定温度的时间的作用.因此,研究冷却水管对高混凝土坝施工过程温度场的影响具有十分重要的工程意义.本文在前人研究的基础上,以ANSYS为平台,以APDL开发语言为工具自行编制了混凝土浇筑过程非稳定温度场的计算程序,验证了程序的准确性,进而以该程序为工具,以龙滩碾压混凝土重力坝浇筑过程为实例,针对天然冷却和有人工冷却措施两种工况进行了温度仿真分析,并研究了大坝浇注完毕后坝体温度场与正常蓄水位下的水荷载耦合作用的应力场分布规律,通过两种工况研究结果对比,分析了人工冷却措施对大坝安全性的影响,得出了一些有益的结论.     

聚亚胺亚胺酮泡沫制备的计算机模拟及其结构表征

以4,4-二-溴二苯甲酮和对苯二胺为单体,在钯催化体系(BINAP/(Pd2(dba)3)作用下得到聚亚胺亚胺酮(PIIK)(Mn=35000,Mw=125000,Mw/Mn=3.57)。通过Materials Studio(MS,version 4.3Accelrys Software Inc.,SanDiego,CA,USA)中的Blends模块对PIIK/Dioxane溶液体系的热致相分离行为进行了计算模拟。模拟结果显示PIIK/Dioxane体系可实现液-液相分离。在理论模拟的支持下,采用热致相分离和冷冻干燥技术成功制备了不同密度的PIIK泡沫,其密度在80～300mg/cm3之间,平均孔径低于5μm。     

Application of orthogonal sampling to incomplete data interferometric tomography: numerical simulation and experimental analysis

Orthogonal projection sampling mode was proposed to reconstruct the incomplete-data flow field in optical computerized tomography (OCT). With numerical simulation technique, a two-peak plane symmetric flow field was reconstructed in different sampling modes and discussed in simulated results is the reconstructive accuracy with error indexes, such as mean square error (MSE) and peak error (PE). The corresponding experiments were researched with a Fabry-Perot rotary interferometer. The results indicated that the errors were drastically reduced and the precision was improved when orthogonal projection sampling mode was adopted in the reconstruction of the incomplete data field. The MSE obtained with orthogonal sampling mode was decreased 72.81% from that of the sequential projection sampling mode (the difference between the MSE obtained with the orthogonal sampling mode and that with the sequential sampling mode divided by the MSE of the sequential sampling mode) and the PE was decreased by 73.97%. The precision obtained from the experimental results reached 10%, which showed the orthogonal projection sampling could be a practicable sampling mode for the incomplete data field reconstruction in OCT and could provide some guidance for the flow-field measurement and apparatus design in the practical situation.     

最小二乘法在尘埃粒子计数器中的应用

分析了导致尘埃粒子计数器标定过程非常复杂的原因,提出将最小二乘法用于尘埃子计数器标定过程中的方法,有利于提高仪器标定的一致性并降低劳动强度,文中给出了用量小二乘法对国产激光尘埃粒子计数器进行标定的实验结果。     

现代企业安全管理方法探讨

分析了企业传统安全管理存在的缺陷,建议运用科学管理方法指导安全生产工作,减少和杜绝事故发生。逐步实现企业本质安全,以适应现代企业发展的需要。     

后小康居住模式展望

本文根据全国一些经济发展快的城市和地区已经超越或即将超越“小康区间”的实情出发 ,提出了“后小康居住模式”,主要有“绿色”、“舒适”、便捷”、“安全”、“多样”和“信息” 6个特征。提出全国按经济水平分类制订有关住宅标准并滚动式发展的设想     

基于衍射且适用于粒径分布反演的半经验公式

基于Fraunhofer Diffraction提出了一种更为确当的适用于粒子尺寸分布反演的半经验公式,在前向小角范围内与精确的Mie解相吻合,其精确度比Fymat Aland Mease KD的近似在不同的范围有了不同程度的提高,特别在粒径很小时有了很大的提高。给出了在此半经验公式下实现粒子尺寸分布反演的两种方法。     

热形变工艺参数对晶界区与晶内区加工硬化程度差别的影响

研究了热形变工艺参数对奥氏体晶粒之间和晶粒内不同区域的形变程度不均匀性的影响,结果表明,晶粒尺寸大小、形变温度和形变量对不同区域的形变程度不均匀性都有影响,从而影响了动态再结晶过程.调节热形变工艺参数可以控制热轧过程中的混晶程度。