Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy me...Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy methods are used to investigate the irradiation damage. The 190keV H ions with a fuence of 1×10^17 cm^-2 are used for implanting pristine and Au ion irradiated Al2O3 to explore the irradiation damage effects on the hydrogen retention in Al2O3. The time-of-flight secondary ion mass spectrometry method is used to obtaJn the single hydrogen depth profile and ions mass spectra （IMS）, in which we find that implanted hydrogens interacted with defects produced by Au ion irradiation. In IMS, we also obtain the hydrogen retention at a certain depth. Comparing the hydrogen retention in different Al2O3 samples, it is concluded that the irradiation damage improves the tritium permeation resistance property of Al2O3 under given conditions. This result means that Al2O3 may strengthen its property of reduc/ng tritium permeation under the harsh irradiation environment in fusion reactors.展开更多
Emergency retention basins (ERB) are diked enclosures alongside rivers into which water from the main river channel is diverted during extreme floods. If the basins are operated during extreme flooding, two negative e...Emergency retention basins (ERB) are diked enclosures alongside rivers into which water from the main river channel is diverted during extreme floods. If the basins are operated during extreme flooding, two negative environmental impacts may occur: 1) contamination of the soils due to their transport by suspended sediments to the basin and 2) depletion of dissolved oxygen in the basin water. A computer-based methodology is presented which was used to assess the environmental risk exhibited by the operation of an ERB system proposed for the Elbe River in Germany. The August 2002 extreme flood event was used as a test case. For such a flood, the results showed that there is a 77% risk that dissolved oxygen levels fall below 2 mg/L in the water and a 48% chance of exceeding the inspection value of 500 mg zinc/kg in the soil.展开更多
目的:在大鼠处于正畸牙保持期时,以全身施药辛伐他汀的方法,来研究其对牙周组织中骨形成蛋白2(bone morphogenetic protein 2,BMP-2)表达的影响。方法:选用78只8周龄雄性Wistar大鼠,随机分成3组。1)空白对照组:将大鼠的前牙实施连轧,将...目的:在大鼠处于正畸牙保持期时,以全身施药辛伐他汀的方法,来研究其对牙周组织中骨形成蛋白2(bone morphogenetic protein 2,BMP-2)表达的影响。方法:选用78只8周龄雄性Wistar大鼠,随机分成3组。1)空白对照组:将大鼠的前牙实施连轧,将其作为支抗,向近中的方向牵移上颌两侧的第一磨牙,持续进行21d之后将其处死。2)构建牙移动模型的对照组,21d之后,在左侧的上颌安装相应的保持装置,各保持1、3、7、14、21、28d,在保持期内,给予注射腹腔生理盐水。3)实验组:改组的保持及加力措施与对照组相同,在保持期期间,给予注射腹腔辛伐他汀。在保持期结束之后,采用免疫组化染色法,并结合定量分析法,对移动牙的牙周组织内的BMP-2水平进行检测和观察。结果:在整个保持期,对照组的BMP-2量逐渐减少,实验组呈逐渐增加的趋势。相同时间的实验用药组与实验对照组比较,实验组的BMP-2量较于对照组普遍要高。除了对照组中的第28天组之外,其余各小组BMP-2的表达强度均强于空白对照组(P<0.01)。结论:腹腔注射辛伐他汀能够增加大鼠实验性牙移动后保持阶段牙周组织中BMP-2的表达,从而促进骨细胞的生成、骨质矿化。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 91426304 and 91226202the National Magnetic Confinement Fusion Energy Research Project under Grant No 2015GB113000
文摘Substantial defects are produced in Al2O3 by 4 MeV Au ion irradiation with a fluence of 4.4×10^15 cm^-2. Ruther- ford baekscattering spectrometry/channeling and cross-sectional transmission electron microscopy methods are used to investigate the irradiation damage. The 190keV H ions with a fuence of 1×10^17 cm^-2 are used for implanting pristine and Au ion irradiated Al2O3 to explore the irradiation damage effects on the hydrogen retention in Al2O3. The time-of-flight secondary ion mass spectrometry method is used to obtaJn the single hydrogen depth profile and ions mass spectra （IMS）, in which we find that implanted hydrogens interacted with defects produced by Au ion irradiation. In IMS, we also obtain the hydrogen retention at a certain depth. Comparing the hydrogen retention in different Al2O3 samples, it is concluded that the irradiation damage improves the tritium permeation resistance property of Al2O3 under given conditions. This result means that Al2O3 may strengthen its property of reduc/ng tritium permeation under the harsh irradiation environment in fusion reactors.
文摘Emergency retention basins (ERB) are diked enclosures alongside rivers into which water from the main river channel is diverted during extreme floods. If the basins are operated during extreme flooding, two negative environmental impacts may occur: 1) contamination of the soils due to their transport by suspended sediments to the basin and 2) depletion of dissolved oxygen in the basin water. A computer-based methodology is presented which was used to assess the environmental risk exhibited by the operation of an ERB system proposed for the Elbe River in Germany. The August 2002 extreme flood event was used as a test case. For such a flood, the results showed that there is a 77% risk that dissolved oxygen levels fall below 2 mg/L in the water and a 48% chance of exceeding the inspection value of 500 mg zinc/kg in the soil.
文摘目的:在大鼠处于正畸牙保持期时,以全身施药辛伐他汀的方法,来研究其对牙周组织中骨形成蛋白2(bone morphogenetic protein 2,BMP-2)表达的影响。方法:选用78只8周龄雄性Wistar大鼠,随机分成3组。1)空白对照组:将大鼠的前牙实施连轧,将其作为支抗,向近中的方向牵移上颌两侧的第一磨牙,持续进行21d之后将其处死。2)构建牙移动模型的对照组,21d之后,在左侧的上颌安装相应的保持装置,各保持1、3、7、14、21、28d,在保持期内,给予注射腹腔生理盐水。3)实验组:改组的保持及加力措施与对照组相同,在保持期期间,给予注射腹腔辛伐他汀。在保持期结束之后,采用免疫组化染色法,并结合定量分析法,对移动牙的牙周组织内的BMP-2水平进行检测和观察。结果:在整个保持期,对照组的BMP-2量逐渐减少,实验组呈逐渐增加的趋势。相同时间的实验用药组与实验对照组比较,实验组的BMP-2量较于对照组普遍要高。除了对照组中的第28天组之外,其余各小组BMP-2的表达强度均强于空白对照组(P<0.01)。结论:腹腔注射辛伐他汀能够增加大鼠实验性牙移动后保持阶段牙周组织中BMP-2的表达,从而促进骨细胞的生成、骨质矿化。
