The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied us...The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied using cross-sectional scanning electron microscope (SEM) images. The intermetallic compound (IMC) growth was analyzed using the empirical power law and a time dependence in the range of 0.26 to 0.33 was found. The morphology of the IMC was investigated by SEM in the temperature range of 235℃ - 290℃, at annealing periods of 10 s, 30 s, and 60 s by selectively etching away the remaining elementary tin. The exposed IMC displays a change in morphology with increasing annealing temperature, demonstrating that the growth velocity of certain crystallographic orientations of the IMC is strongly influenced by the annealing temperature. Additionally, coarsening and crumbling of the IMC grains is observed, and will be discussed with respect to the responsible mechanisms.展开更多
The microstructures of fault rocks from the Wasatch fault zone in Utah （USA） have been studied using a polarizing microscope,a scanning electron microscope （SEM） and an ultrahigh-voltage electron microscope （HVHM...The microstructures of fault rocks from the Wasatch fault zone in Utah （USA） have been studied using a polarizing microscope,a scanning electron microscope （SEM） and an ultrahigh-voltage electron microscope （HVHM）.This fault zone may be recognized as one a with long history of seismic activity according to the microstructural characteristics such as type, deformation characteristics,melting structure and surface textures of the fault rocks.However,the main fault now present seems not to have been noticeably active since the late Pleistocene （Q<sub>3</sub>）,as shown by the eroded-surface texture on the quartz fragments in the fault gouge.Meanwhile,those faults supposed to be strongly active in modern times are branching faults much closer to the basin side and are covered by the Holocene sediments in the basin.展开更多
The ENT pathologies are not well known to the populations of our developing countries. This lack of knowledge leads certain subjects to have attitudes and practices that favor their occurrence and/or their aggravation...The ENT pathologies are not well known to the populations of our developing countries. This lack of knowledge leads certain subjects to have attitudes and practices that favor their occurrence and/or their aggravation. The objective of this study was to assess the knowledge and describe the attitudes and practices of patients facing ENT pathologies at the Conakry Hospital and University Center (CHU). This was a prospective, descriptive study lasting six months (June-November 2018). Among the 1410 patients who had consulted in the department during the study period, 1102 had participated in the survey, or 78.16% of cases. The mean age of the patients was 39.3 ± 17.3 years, predominantly female, for a sex ratio of 0.75. The majority of patients were of university education (41.02%) and civil servants (38.66%) represented the dominant socio-professional layer. Rhino-sinusitis (30.85%) and ear infections (20.14%) were the most common pathologies. Almost a third (32.85%) of respondents had no knowledge of behaviors harmful to ENT health. More than half (52.45%) of the patients did not know of any factors favoring the occurrence of ENT pathologies. The therapeutic orientation had been made towards modern medicine in 63.52% against 4.54% for traditional medicine. The choice of self-medication concerned 31.94% of patients. This survey showed that patients have limited knowledge of ENT pathologies as well as the attitudes and practices likely to favor their occurrence. However, a multicenter study involving a larger proportion of patients will confirm these data.展开更多
文摘The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied using cross-sectional scanning electron microscope (SEM) images. The intermetallic compound (IMC) growth was analyzed using the empirical power law and a time dependence in the range of 0.26 to 0.33 was found. The morphology of the IMC was investigated by SEM in the temperature range of 235℃ - 290℃, at annealing periods of 10 s, 30 s, and 60 s by selectively etching away the remaining elementary tin. The exposed IMC displays a change in morphology with increasing annealing temperature, demonstrating that the growth velocity of certain crystallographic orientations of the IMC is strongly influenced by the annealing temperature. Additionally, coarsening and crumbling of the IMC grains is observed, and will be discussed with respect to the responsible mechanisms.
文摘The microstructures of fault rocks from the Wasatch fault zone in Utah （USA） have been studied using a polarizing microscope,a scanning electron microscope （SEM） and an ultrahigh-voltage electron microscope （HVHM）.This fault zone may be recognized as one a with long history of seismic activity according to the microstructural characteristics such as type, deformation characteristics,melting structure and surface textures of the fault rocks.However,the main fault now present seems not to have been noticeably active since the late Pleistocene （Q<sub>3</sub>）,as shown by the eroded-surface texture on the quartz fragments in the fault gouge.Meanwhile,those faults supposed to be strongly active in modern times are branching faults much closer to the basin side and are covered by the Holocene sediments in the basin.
文摘The ENT pathologies are not well known to the populations of our developing countries. This lack of knowledge leads certain subjects to have attitudes and practices that favor their occurrence and/or their aggravation. The objective of this study was to assess the knowledge and describe the attitudes and practices of patients facing ENT pathologies at the Conakry Hospital and University Center (CHU). This was a prospective, descriptive study lasting six months (June-November 2018). Among the 1410 patients who had consulted in the department during the study period, 1102 had participated in the survey, or 78.16% of cases. The mean age of the patients was 39.3 ± 17.3 years, predominantly female, for a sex ratio of 0.75. The majority of patients were of university education (41.02%) and civil servants (38.66%) represented the dominant socio-professional layer. Rhino-sinusitis (30.85%) and ear infections (20.14%) were the most common pathologies. Almost a third (32.85%) of respondents had no knowledge of behaviors harmful to ENT health. More than half (52.45%) of the patients did not know of any factors favoring the occurrence of ENT pathologies. The therapeutic orientation had been made towards modern medicine in 63.52% against 4.54% for traditional medicine. The choice of self-medication concerned 31.94% of patients. This survey showed that patients have limited knowledge of ENT pathologies as well as the attitudes and practices likely to favor their occurrence. However, a multicenter study involving a larger proportion of patients will confirm these data.
