消化内镜下缝合术治疗十二指肠巨大穿孔5例的疗效分析

目的将消化内镜下缝合术运用于十二指肠巨大穿孔,采用内镜下闭合穿孔来避免外科手术。方法单腔镜下运用尼龙圈联合钛夹闭合十二指肠穿孔。结果该组5例十二指肠巨大穿孔的患者均在单腔镜下运用荷包缝合成功闭合穿孔,无1例中转外科手术。结论单腔镜荷包缝合术运用于十二指肠巨大穿孔是有效可行的。

The development,performances and applications of the monochromatic X-rays facilities in(0.218–301)keV at NIM,China

Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the universe.Countries worldwide have launched numerous space exploration satellites.Accurate calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational results.For the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,P.R.China(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke V.These facilities have a high performance in terms of energy stability,monochromaticity,and flux stability.The monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 h.Calibration experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the facilities.Thus far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in progress.This study will contribute to the advancement of X-ray astronomy the development of Chinese space science.

Transition edge sensor-based detector:from X-ray to γ-ray

A transition edge sensor(TES)is extremely sensitive to changes in temperature,and combined with a high-Z metal of a certain thickness,it can realize high-energy resolution measurements of particles such as X-rays.X-rays with energies below 10 keV have a weak penetrating ability,hence,only gold or bismuth of a few micrometers in thickness can guarantee a quantum efficiency higher than 70%.Therefore,the entire structure of the TES X-ray detector in this energy range can be realized using a microfabrication process.However,for X-rays or γ-rays from 10 keV to 200 keV,submillimeter absorber layers are required,which cannot be realized using the microfabrication process.This paper first briefly introduces a set of TES X-ray detectors and their auxiliary systems,and then focuses on the introduction of the TES γ-ray detector with an absorber based on a submillimeter lead-tin alloy sphere.The detector achieved a quantum efficiency above 70% near 100 keV and an energy resolution of approximately 161.5 eV at 59.5 keV.

Establishment and study of a polarized X-ray radiation facility

With the advancement in X-ray astronomical detection technology,various celestial polarization detection projects have been initiated.To meet the calibration requirements of polarimeters on the ground,a polarized X-ray radiation facility was designed for this study.The design was based on the principle that X-rays incident at 45°on a crystal produce polarized X-rays,and a second crystal was used to measure the polarization of the X-rays produced by the facility after rotation.The effects of different diaphragm sizes on the degree of polarization were compared,and the facility produced X-rays with polarization degrees of up to 99.55±0.96%using LiF200 and LiF220 crystals.This result revealed that the polarization of incident X-rays is one of the factors affecting the diffraction efficiency of crystals.The replacement of different crystals can satisfy the calibration requirements of polarized X-ray detectors with more energy points in the energy range(4-10)keV.In the future,the facility should be placed in a vacuum environment to meet the calibration requirements at lower energies.

Absolute measurement of radiant power for synchrotron radiation monochromatized X-rays

Purpose Absolute measurement of radiant power in the X-ray region is essential for many applications in astrophysics,spectroscopy,and X-ray diagnostics.This paper presents a dependable method of absolute measurement of radiant power for synchrotron radiation monochromatized X-rays.Methods A free-air ionization chamber was examined closely and employed as the detector in the present work.Its measuring principle was discussed,and the correction factors were determined.Absolute measurement of radiant power for synchro-tron radiation monochromatized X-rays in the region of 6-20 keV was performed using the free-air ionization chamber at Beijing Synchrotron Radiation Facility.As a verification and an important application,photodiodes were calibrated against the free-air ionization chamber.Results Relative standard uncertainties of absolute measurement using free-air ionization chamber are about 1%.Calibration of photodiodes within the photon energy range from 6 to 20 keV has relative standard uncertainties below 1.5%.Conclusion The free-air ionization chamber is qualified to be used in many disciplines to support the measurement of opti-cal radiation.