A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wav...A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wave steepness, and small elevation of the wall above the mean water level. Caisson breakwaters can withstand some exceptionally high impulsive force peaks (even twice the weight in still water);whereas, with the same sea state and weight, a breakwater composed of layers of solid concrete blocks is destroyed.展开更多
Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes t...Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes the background and the rationale for these experiments,how they were organized and executed,main areas of research covered during these experiments,main results,contributions to mainstream fusion research,and discusses lessons learned and outcomes from these activities.We underline several of the most important scientific outputs and also specific outputs in the education of young scientists and scientists from developing countries and their importance.展开更多
AIM To assess the feasibility and safety of a novel enteroscope,negative-pressure suction endoscope in examining the small intestine of a porcine model.METHODS In vitro experiments in small intestinal loops from 20pig...AIM To assess the feasibility and safety of a novel enteroscope,negative-pressure suction endoscope in examining the small intestine of a porcine model.METHODS In vitro experiments in small intestinal loops from 20pigs and in vivo experiments in 20 living pigs were conducted.RESULTS In in vitro experiments,a negative pressure of>0.06MPa was necessary for optimal visualization of the intestine,and this pressure did not cause gross or histological damage to the mucosa.For satisfactory examination of the small intestine in vivo,higher negative pressure(>1.00 MPa)was required.Despite this higher pressure,the small intestine did not show any gross or microscopic damage in the suctioned areas.The average time of examination in the living animals was 60±7.67 min.The animals did not experience any apparent ill effects from the procedure.CONCLUSION Small intestine endoscope was safely performed within a reasonable time period and enabled complete visualization of the intestine in most cases.展开更多
A theoretical model which describes the small-scale irregularities excited by powerful high frequency （3–30 MHz） electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is...A theoretical model which describes the small-scale irregularities excited by powerful high frequency （3–30 MHz） electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is based on the transport equation in magnetic plasma and mode conversion from electromagnetic wave to electrostatic wave in ionospheric modification.Threshold electric field for exciting small-scale （meter scale） irregularities and spatial spectra of irregularities are analytically calculated by this model. The results indicate that background electron density and geomagnetic field play an important role for the threshold electric field and the spatial scale of the electron density irregularities. The results demonstrate that the electric field threshold increases with the decrease of the spatial scale of the irregularities. For exciting meter scale irregularities, the threshold electric field is about tens of mV m^（-1）. The theoretical results are consistent with those of the experiments.展开更多
Small H-beams such as the No.14–20 I-steel can be inserted into soil-cement retaining walls to form small H-beam soil-cement compound walls, functioning both as a retaining wall and a cutoff wall for braced structure...Small H-beams such as the No.14–20 I-steel can be inserted into soil-cement retaining walls to form small H-beam soil-cement compound walls, functioning both as a retaining wall and a cutoff wall for braced structure excavations. Being different from the mixed soil-cement wall (SMW), the interaction between soil-cement and small H-steel is very good. We have carried out a series of bending experiments on small H-beams in soil-cement model compound beams to study the mechanism of interactions. The results show that the interaction between H-beams and soil-cement is very good, whether the H-beam is single or double. Joint forms of double H-beams at one end have little effect on both the contribution coefficient and on ultimate deflection before cracking. But after cracking, the joint forms greatly affect the contribution coefficient. We conclude that the rigid joint girder for double H-beams is a better choice in practice.展开更多
文摘A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wave steepness, and small elevation of the wall above the mean water level. Caisson breakwaters can withstand some exceptionally high impulsive force peaks (even twice the weight in still water);whereas, with the same sea state and weight, a breakwater composed of layers of solid concrete blocks is destroyed.
基金supported by funding by the IAEA technical contracts within IAEA Coordinated Research Projects on‘Joint Research Using Small Tokamaks’and on‘Utilisation of a Network of Small Magnetic Confinement Fusion Devices for Mainstream Fusion Research’funded by Russian Science Foundation,Project 19-12-00312+3 种基金partly supported by the Competitiveness Program of NRNU MEPhIthe partial financial support from MEPhI and NRU MPEI in the framework of the Russian Academic Excellence Projectsupported by Tokamak Energy LtdOxford Instruments(UK)。
文摘Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes the background and the rationale for these experiments,how they were organized and executed,main areas of research covered during these experiments,main results,contributions to mainstream fusion research,and discusses lessons learned and outcomes from these activities.We underline several of the most important scientific outputs and also specific outputs in the education of young scientists and scientists from developing countries and their importance.
文摘AIM To assess the feasibility and safety of a novel enteroscope,negative-pressure suction endoscope in examining the small intestine of a porcine model.METHODS In vitro experiments in small intestinal loops from 20pigs and in vivo experiments in 20 living pigs were conducted.RESULTS In in vitro experiments,a negative pressure of>0.06MPa was necessary for optimal visualization of the intestine,and this pressure did not cause gross or histological damage to the mucosa.For satisfactory examination of the small intestine in vivo,higher negative pressure(>1.00 MPa)was required.Despite this higher pressure,the small intestine did not show any gross or microscopic damage in the suctioned areas.The average time of examination in the living animals was 60±7.67 min.The animals did not experience any apparent ill effects from the procedure.CONCLUSION Small intestine endoscope was safely performed within a reasonable time period and enabled complete visualization of the intestine in most cases.
基金supported by National Natural Science Foundation of China(NSFC grants 41204111,4157414641774162 and 41704155)China Postdoctoral Science Foundation(2017M622504)
文摘A theoretical model which describes the small-scale irregularities excited by powerful high frequency （3–30 MHz） electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is based on the transport equation in magnetic plasma and mode conversion from electromagnetic wave to electrostatic wave in ionospheric modification.Threshold electric field for exciting small-scale （meter scale） irregularities and spatial spectra of irregularities are analytically calculated by this model. The results indicate that background electron density and geomagnetic field play an important role for the threshold electric field and the spatial scale of the electron density irregularities. The results demonstrate that the electric field threshold increases with the decrease of the spatial scale of the irregularities. For exciting meter scale irregularities, the threshold electric field is about tens of mV m^（-1）. The theoretical results are consistent with those of the experiments.
文摘Small H-beams such as the No.14–20 I-steel can be inserted into soil-cement retaining walls to form small H-beam soil-cement compound walls, functioning both as a retaining wall and a cutoff wall for braced structure excavations. Being different from the mixed soil-cement wall (SMW), the interaction between soil-cement and small H-steel is very good. We have carried out a series of bending experiments on small H-beams in soil-cement model compound beams to study the mechanism of interactions. The results show that the interaction between H-beams and soil-cement is very good, whether the H-beam is single or double. Joint forms of double H-beams at one end have little effect on both the contribution coefficient and on ultimate deflection before cracking. But after cracking, the joint forms greatly affect the contribution coefficient. We conclude that the rigid joint girder for double H-beams is a better choice in practice.
