With great interest we read the recent retrospectice study by Barta et al （1） dealing with the clinical presentation of patients with microscopic colitis. They investigated in a cohort of 53 patients with microscopi...With great interest we read the recent retrospectice study by Barta et al （1） dealing with the clinical presentation of patients with microscopic colitis. They investigated in a cohort of 53 patients with microscopic colitis （46 with collagenous colitis, 7 with lymphocytic colitis） the relationship between microscopic colitis and both constipation and diarrhea. One of their mean finding was that abdominal pain, diarrhea and constipation was a common symptom complex of patients with microscopic colitis, thus the face of microcopic colitis resembles the subgroups of irritable bowel syndrome （IBS）.展开更多
This paper studied the wear characteristics as well as the wear mechanism of the Ni-P alloy brush-plating coating by means of sliding-wear tests, SEM and X Ray analyses. The results show that Ni-Palloy coating has exc...This paper studied the wear characteristics as well as the wear mechanism of the Ni-P alloy brush-plating coating by means of sliding-wear tests, SEM and X Ray analyses. The results show that Ni-Palloy coating has excellent wear-ability in high temperature, and the wear mechanism of the coating is that both the adhesive wear and abrasive wear exist in a boundary lubrication condition. The wear model was built up.展开更多
The structure, working principles, and main technological parameters of the premajet derusting machine are introduced. Experiments were made to test the relationship among such jet parameters as working pressure, rate...The structure, working principles, and main technological parameters of the premajet derusting machine are introduced. Experiments were made to test the relationship among such jet parameters as working pressure, rate of water flow, abrasive weight consistency and derusting efficiency. Reasonable parameters were decided. Results prove that the derusting machine is characterized by its high derusting efficiency (as high as 20m 2/h), good derusting quality (as good as ISO8501 1 Sa 2.5), and low specific power consumption (about 0.3kW·h/m 2). Therefore it is a new type of high efficiency derusting machine.展开更多
The new designed at Institute for High Energy Physics （IHEP） technologies ot polystyrene sclntmatol~ ll,aJJu,a 5, molding of polystyrene granules under pressure, melting of granules in forms with mirrors wails, prod...The new designed at Institute for High Energy Physics （IHEP） technologies ot polystyrene sclntmatol~ ll,aJJu,a 5, molding of polystyrene granules under pressure, melting of granules in forms with mirrors wails, production of scintillating granules and detectors on their basis are considered. The main characteristics of the polystyrene scintillators produced by a method of large-block polymerization and a method of extruding of scintillation strips from polymerized blocks are provided in this article also.展开更多
The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-progr...The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-programmed desorption method are presented. It has been shown that HE is adsorbed as four forms, differing in the structure, temperature, order and activation energy of desorption： HEads, HE＋ads, Hads, Hat （Tdes 〉 873 K）. The relationship of activity and selectivity of Pt-Ru catalysts with the presence of active centers able to adsorb atomic hydrogen with desorption energy （Edes） = 60-70 kJ/mol in the catalytic oxidation of methane was determined. It was found that the O2 adsorbed as two forms differing in the structure, temperature and activation energy of desorption. It has been determined that changing the atomic ratio of elements in the catalysts significantly affect on the adsorption Of OE. The introduction of ruthenium into the platinum catalyst increases the oxygen adsorption; and the surface is stabilized in a homogeneous state. Quantum chemical calculations of the activation of C-H bonds in a molecule of methane on Ru,,Pt, （m ＋ n = 4） clusters have been carried out.展开更多
The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has succe...The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has successfully developed a new method for effectively synthesizing formamide compounds from CO_2,H2 and primary or secondary amines serving as the feedstocks.展开更多
In this review, we discuss our recent advances in modeling adhesive wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile ...In this review, we discuss our recent advances in modeling adhesive wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile shearing of an asperity to the formation of a debris particle. This transition occurs at a critical junction size, which determines the particle size at its birth. Atomistic simulations also reveal that for nearby asperities, crack shielding mechanisms result in a wear volume proportional to an effective area larger than the real contact area. As the density of microcontacts increases with load, we propose this crack shielding mechanism as a key to understand the transition from mild to severe wear. We conclude with open questions and a road map to incorporate these findings in mesoscale continuum models. Because these mesoscale models allow an accurate statistical representation of rough surfaces, they provide a simple means to interpret classical phenomenological wear models and wear coefficients from physics-based principles.展开更多
文摘With great interest we read the recent retrospectice study by Barta et al （1） dealing with the clinical presentation of patients with microscopic colitis. They investigated in a cohort of 53 patients with microscopic colitis （46 with collagenous colitis, 7 with lymphocytic colitis） the relationship between microscopic colitis and both constipation and diarrhea. One of their mean finding was that abdominal pain, diarrhea and constipation was a common symptom complex of patients with microscopic colitis, thus the face of microcopic colitis resembles the subgroups of irritable bowel syndrome （IBS）.
文摘This paper studied the wear characteristics as well as the wear mechanism of the Ni-P alloy brush-plating coating by means of sliding-wear tests, SEM and X Ray analyses. The results show that Ni-Palloy coating has excellent wear-ability in high temperature, and the wear mechanism of the coating is that both the adhesive wear and abrasive wear exist in a boundary lubrication condition. The wear model was built up.
文摘The structure, working principles, and main technological parameters of the premajet derusting machine are introduced. Experiments were made to test the relationship among such jet parameters as working pressure, rate of water flow, abrasive weight consistency and derusting efficiency. Reasonable parameters were decided. Results prove that the derusting machine is characterized by its high derusting efficiency (as high as 20m 2/h), good derusting quality (as good as ISO8501 1 Sa 2.5), and low specific power consumption (about 0.3kW·h/m 2). Therefore it is a new type of high efficiency derusting machine.
文摘The new designed at Institute for High Energy Physics （IHEP） technologies ot polystyrene sclntmatol~ ll,aJJu,a 5, molding of polystyrene granules under pressure, melting of granules in forms with mirrors wails, production of scintillating granules and detectors on their basis are considered. The main characteristics of the polystyrene scintillators produced by a method of large-block polymerization and a method of extruding of scintillation strips from polymerized blocks are provided in this article also.
文摘The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-programmed desorption method are presented. It has been shown that HE is adsorbed as four forms, differing in the structure, temperature, order and activation energy of desorption： HEads, HE＋ads, Hads, Hat （Tdes 〉 873 K）. The relationship of activity and selectivity of Pt-Ru catalysts with the presence of active centers able to adsorb atomic hydrogen with desorption energy （Edes） = 60-70 kJ/mol in the catalytic oxidation of methane was determined. It was found that the O2 adsorbed as two forms differing in the structure, temperature and activation energy of desorption. It has been determined that changing the atomic ratio of elements in the catalysts significantly affect on the adsorption Of OE. The introduction of ruthenium into the platinum catalyst increases the oxygen adsorption; and the surface is stabilized in a homogeneous state. Quantum chemical calculations of the activation of C-H bonds in a molecule of methane on Ru,,Pt, （m ＋ n = 4） clusters have been carried out.
文摘The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has successfully developed a new method for effectively synthesizing formamide compounds from CO_2,H2 and primary or secondary amines serving as the feedstocks.
文摘In this review, we discuss our recent advances in modeling adhesive wear mechanisms using coarse-grained atomistic simulations. In particular, we present how a model pair potential reveals the transition from ductile shearing of an asperity to the formation of a debris particle. This transition occurs at a critical junction size, which determines the particle size at its birth. Atomistic simulations also reveal that for nearby asperities, crack shielding mechanisms result in a wear volume proportional to an effective area larger than the real contact area. As the density of microcontacts increases with load, we propose this crack shielding mechanism as a key to understand the transition from mild to severe wear. We conclude with open questions and a road map to incorporate these findings in mesoscale continuum models. Because these mesoscale models allow an accurate statistical representation of rough surfaces, they provide a simple means to interpret classical phenomenological wear models and wear coefficients from physics-based principles.
