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To make paper more systematic and practical, this paper has first introduced the development history of CT equipment, then, elaborate construction of system and theworking principle of CT equipment systematically, including the property of X-ray, the absorption law of X-ray for materials, the reconstruction principle of CT image, the structure of software and hardware for CT equipment. Finally, with 2 CT systems that we used, statistic and analysis of all the malfunctions which have carried out in passed 10 years was given, and according to the systematic parts of fault located, classify the malfunctions, then elaborate their working principle one by one, analyze the regularity and the characteristic of each malfunction, and put forward specific prevention method and measure for the malfunction.

为了使论文更具系统性和实用性，本论文首先介绍了CT设备的发展史，然后比较系统地阐述CT设备的工作原理及系统结构，包括X射线的特性和物质对x射线的吸收规律，CT图像的重建原理，CT设备的软、硬件结构等，最后以我们所使用的2台CT为例，对10余年来所出现的故障进行了全面的统计分析，并按故障所处的系统部件进行分类，然后逐个阐述其工作原理，分析其故障的特点和规律，并就这些故障提出具体的预防方法和措施。

Alternatively, the spectral softening above 2 GeV could be due to gamma-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (l~100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

另外的关于2 GeV以上能谱变软的可能解释是高能光子和寄主活动星系核的软X射线辐射场通过电子对产生反应而被吸收，但是这个解释要求反应区域要很靠近中心黑洞(1~100倍引力半径)，这和3C 454.3的X射线测量谱相矛盾。

A new concept of the X-M-PN space is introduced, and the acute angle principle in the X-M-PN space is proved.

提出了X-M-PN空间的新概念，在X-M-PN空间中证明了锐角原理，同时得到了若干新的结果。

If the acute angle of the parallelogram is x , find x .

该平 四边形的锐角是 x°，求 x。

Our result has demonstrated that synchrotron X-rays have similar damage effects to SAMs with –CH3 or O=C-OH tail group, and S-Ag bond is much resistant to X-ray induced damage than S-Au bond.

因此，以比较硫-金属键结强度的方法来做为受到同步辐射X光破坏程度的指标，本研究显示：同步辐射X光对-CH3及O=C-OH尾端官能基之硫醇分子的破坏作用相近，且S-Ag键结抵抗X光破坏能力比S-Au为强。

Two soft X ray spectrometers are used to measure X ray spectra of primary and secondary disk respectively.The property that X ray spectra were modified on secondary disk is investigated.

测量结果表明：这种结构的双盘靶基本上能避免初级盘喷射等离子体的影响，初级盘后向辐射的X光谱具有明显的N和O带谱结构，而次级辐射的X光谱主要以O带为主。

Most of the developing X-Y tables applied Ball screw-driven table system or piezo-ceramic linear motor by taking the advantages of carrying heavy loads. However, their cost are very high in contrast to the proposed architecture. In some particular application fields. Carrying heavy loads is not the main requirement for the X-Y table, such as organic cell inspection, optical fiber alignment, nano-material research, ect. Taking this idea as a premise, if we could able to create a precise positioning X-Y table with very low cost, we will be able to achieve the extremely high commercial value and highly competitive ability.

X-Y精密定位平台的开发，不外乎线性马达或压电陶瓷马达搭配导螺杆或其它机构所组成，其优点是可以承载较重之待测物体，缺点是重量大且价格昂贵，在许多应用上并不要求测试平台拥有太大的荷重能力，如生物医学诊断及检测，生物晶片开发及检测，光纤校准，奈米材料研发，奈米量测及精密全平面扫描等等，如果以此为前提，能以极低之成本创造出高精密定位之X-Y平台，将会有极高之商业价值及极大之竞争力。

Shots' experimental results show that the X-ray calorimeters are stable, the sensitivity of calorimeter is (84.1±3.4)μV/mJ and the related combined standard uncertainty in the X-ray energy measure is about 31%.

结果表明：X光量热计性能稳定，其灵敏度？？84.1±3.4μV/mJ，X光能量测量的相对合成标准不确定度约为31%，可用于X光定量测量。

Two soft X-ray spectrometers were used to measure X-ray radiation from the primary and secondary disks, respectively.

采用两台软X射线谱仪分别对初级和次级辐射的X射线进行测量，采用X射线条纹相机测量双盘靶等离子体喷射的时空扫描图象，并对实验结果进行简单的物理分析。

This paper introduces the studies of the ultra-short Thomson scattering X-ray source at the accelerator laboratory of Tsinghua University in recent years. Properties such as the photon yield,the pulse length and time jitter of the produced photon pulse were predicted theoretically from the parameters of the electron bunch and the laser pulse,and the scattering angle. Preliminary experiments were successfully carried out with a 16 MeV backward-traveling-wave accelerator and the ns-Q switched laser provided by China Academy of Engineering Physics. This paper also introduces the 1.6-cell electron gun that was fabricated on site and the experiment with high RF power including the measurement of the electron bunche parameters. Based on these,we have designed an X-ray source,which is now under construction.

介绍了清华大学加速器实验室近年来关于汤姆逊散射超短X射线源的研究工作；研究了在任意散射角度下电子束参数和激光束参数对散射光子参数的影响，给出了散射光子的参数如光子产额、脉冲长度、时间抖动等与电子束参数、激光束参数和散射角度的关系；利用实验室已有的16 MeV反波行波加速器与中国工程物理研究院激光聚变研究中心提供的ns调Q激光搭建了汤姆逊散射初步实验平台并开展了实验研究；加工了1.6-cell光阴极微波电子枪，搭建了高功率实验平台，对产生的电子束参数进行了初步测量；对汤姆逊散射超短X射线源进行了设计并开展了相关的平台建设工作，对产生的X射线脉冲参数进行了模拟。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。