高千伏CR和低千伏CR胸部摄影图像现实效果比较

目的:探讨从影像显示效果方面考虑,胸部CR是否有必要使用高千伏摄影.方法:胸部后前位摄影100例,随机分为两组,75KV和120KV各50例,观察对比显示效果.结果:使用75KV进行胸部后前位CR摄影时,肺野外带肺纹理和左心室后肺纹理显示清晰程度不及120KV.结论:从影像视觉评价结果来看,应用CR系统进行胸部摄影,依然应该选择高千伏拍摄较为合适.     

射线检测在复合材料无损检测中的应用

随着新型复合材料的迅速开发和应用，其制造过程监测、产品缺陷检测及质量评价等已成为不可缺少的环节。射线检测技术在复合材料无损评价中占有极其重要的地位。对现有的主要射线检测方法，包括X射线照相法、X射线实时成像法、射线计算机断层扫描法、射线断层形貌成像法、康普顿散射法及中子照相法等在复合材料质量评价中的应用状况进行了简要的评述，并指出复合材料射线检测的发展趋势。     

射线数字成像检测技术

介绍多种射线数字成像(DR)系统的组成及成像机理，分析其性能指标、优缺点及应用领域。光子放大的DR系统(如图像增强器DR系统)实时性好，但适应的射线能量低，检测灵敏度相对较低；其它系统的检测灵敏度较高但成像时间较长。DR系统成像方式的主要区别在于射线探测器，除射线转换方式外，影响系统检测灵敏度的主要因素是散射噪声和量子噪声；可采用加准直器和光量子积分降噪的方法提高检测灵敏度。     

丝素蛋白/羟基磷灰石多孔复合材料修复骨缺损研究

为了探讨丝素蛋白/羟基磷灰石(SF/HA)复合多孔支架材料的制备及其用于骨缺损的修复,采用超声波凝胶干燥法制备了SF/HA复合材料;以脱胶茧丝为增强材料,水溶性淀粉为制孔剂,通过去离子水萃取法除去淀粉,制备了SF/HA多孔复合材料。对其孔隙率及抗压强度进行测试,并将其植入兔股骨缺损处观察修复的情况。SF/HA多孔复合材料的孔隙率接近75%,孔径尺寸分布约从几微米到400μm,并且孔隙之间相互贯通,其抗压强度可达10 MPa以上,植入兔股骨缺损处未见引起骨组织明显的炎症反应及骨坏死,术后12周发现基本修复骨缺损部位,而空白对照组没有骨生成。SF/HA多孔复合材料可以满足骨组织工程支架的基本要求,用于骨缺损的修复。     

Portable pulsed electronic digital X-ray imager

A portable, pulsed electronic digital X-ray imaging device has been developed. The system is intended to be used in explosive ordnance disposal, police and customs baggage inspection and nondestructive testing (NDT). Image acquisition is performed by a charge-coupled-device (CCD) imaging sensors which view the output of an X-ray scintillation screen via an optical system. The construction of the system, its specifications, and test results are presented.     

射线实时成像检验技术与射线照相检验技术的等价性讨论

在分析射线照相检验技术的有关规定的基础上，提出了射线实时成像检验技术在与射线照相检验技术具有同等缺陷检验能力情况下的等价性指标。对射线实时成像检验技术的应用具有重要意义。     

Roadway Heaving Caused by High Organic Matter

A forensic study was conducted to investigate the premature pavement failure of heaving and cracking on the north bound lane of SH6 and to determine (1) the causes of the heaving and cracking; (2) the severity and extent of the problem; and (3) a prevention strategy. Ground penetration radar (GPR), falling weight deflectometer (FWD), dynamic cone penetrometer (DCP), and soil boring and laboratory tests were conducted. Soil maps provided by the Natural Resource Conservation Service (NRCS) and the electrical resistivity tomography (ERT) were utilized to locate areas that may have similar problems for the ongoing project. It was concluded that the heaving was caused by high organic content in soils. The low pH of the lime treated subgrade layer indicated that the lime stabilization was ineffective. This was due to the high concentration of organic matter. FWD and DCP results indicated that the heaved/cracked areas are losing structural load support. Approximately 84% of the bumps/dips detected by the profiler were also detected by the GPR. Based on the GPR results, it was estimated that about 1.2?miles of the roadway may have potential heaving in the future. Although it is not a standard practice to determine the organic content of soil for new construction, it is critical to determine the organic matter through soil boring and laboratory testing in the suspicious areas. It was found that the soil maps provided by the NRCS yielded a reasonable estimate, and can be used as a screening tool. All five locations (O1 to O5) identified by ERT were verified by boring and laboratory tests to have high organic content (1.9–3.3%). Boring results indicated that ERT was able to map the soil strata and could differentiate between sandy and clay soil types. Although ERT was able to identify the anomalies with high organic contents, and the results were confirmed by boring and laboratory testing, additional work is needed to refine the procedure.     

Multi-sequence dome lay-up simulations for hydrogen hyper-bar composite pressure vessels

The aim of this study is to propose a calculation method for predicting the geometrical characteristics of the end-closures of composite pressure vessels used in gaseous hydrogen storage applications. We present here a method for predicting the characteristics of domes made by multi-sequence lay-up and subject to changes in winding angle and thickness. In the proposed model, winding angle and thickness calculations are based on two existing methods that have been investigated in a single dome lay-up context. Using them for multi-sequence dome lay-up calculation is the originality of this work. The first predictive results are compared with experimental pressure vessel data and discussed. A good correlation between the theoretical approach and the experiments was found, indicating that the predictions could be helpful in a procedure of overall optimisation.     

工业射线照相影像质量评价

射线照相影像质量对保证工业射线无损探伤检测的可靠性和有效性具有重要意义。本文概述射线照相影像质量三要素一对比度，不清晰度和颗粒度的涵义，并重点介绍像质核心-射线照相三维灵敏度（对比灵敏度，细节灵敏度和裂纹灵敏度）的评价方法。本文分六个部分：1，概述，2，射线照相对比度；3，射线照相清晰度；4，颗粒性和颗粒度；5，信噪比；6、射线照相灵敏度。本期刊登其1和2两部分，其他部分将在以后各期陆续刊出。     

Neural Network Based Thickness Estimation from Multiple Radiographic Images

Back propagation (BP) type artificial neural networks (ANN) have been trained and used for thickness estimations from radiographic images. Test objects have been assembled from different materials and radiographic images of the test objects were obtained for thickness estimations. While some of the study has been based on the synthetic images formed through the radiographic simulation program XRSIM, the rest of the study has used actual radiographic images. The average estimation errors were 7% and 9% when two and three synthetic radiographic images obtained at different x-ray tube settings were used. With the actual images, the thickness of only one of the materials has been estimated and the material was identified. This has been due to the fact that scattering of x-rays by the test object results in a non uniform gray scale variation in the radiographic images even though the object thickness is uniform.