Numerical modeling of three cases(Fuka Mine,Okayama;Shouda Mine,Okayama;Tokiwa Mine,Fukushima)of mining in Japan using FLAC(fast Lagrangian analysis of continua)is introduced to evaluate the stability of hilltop excav...Numerical modeling of three cases(Fuka Mine,Okayama;Shouda Mine,Okayama;Tokiwa Mine,Fukushima)of mining in Japan using FLAC(fast Lagrangian analysis of continua)is introduced to evaluate the stability of hilltop excavation.Ubiquitous joint model is adopted to account for the presence of weak planes,such as weathering joints,bedding planes,in FLAC Mohr-Coulomb mode.By studying the distribution of stress,displacement and safety factor,the stability of excavation can be evaluated and new suggestions based on the numerical modeling process can be presented.Further consideration and methodology of the numerical modeling method are also discussed.展开更多
Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the id...Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption im-ages. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.展开更多
Let G be a semitopological semigroup. Let C be a nonempty subset of a Hilbert space and J ={T t:t∈G} be a representation of G as asymptotically nonexpansive type mappings of C into itself such ...Let G be a semitopological semigroup. Let C be a nonempty subset of a Hilbert space and J ={T t:t∈G} be a representation of G as asymptotically nonexpansive type mappings of C into itself such that the common fixed point set F(J) of J in C is nonempty. It is proved that ∩s∈G co {T ts x:t∈G}∩F(J) is nonempty for each x ∈ C if and only if there exists a nonexpansive retraction P of C onto F(J) such that PT s=T sP=P for all s∈G and P(x) is in the closed convex hull of {T sx:s∈G}, x∈C . This result shows that many key conditions in [1-4, 9, 12-15 ] are not necessary.展开更多
文摘Numerical modeling of three cases(Fuka Mine,Okayama;Shouda Mine,Okayama;Tokiwa Mine,Fukushima)of mining in Japan using FLAC(fast Lagrangian analysis of continua)is introduced to evaluate the stability of hilltop excavation.Ubiquitous joint model is adopted to account for the presence of weak planes,such as weathering joints,bedding planes,in FLAC Mohr-Coulomb mode.By studying the distribution of stress,displacement and safety factor,the stability of excavation can be evaluated and new suggestions based on the numerical modeling process can be presented.Further consideration and methodology of the numerical modeling method are also discussed.
文摘Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption im-ages. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.
文摘Let G be a semitopological semigroup. Let C be a nonempty subset of a Hilbert space and J ={T t:t∈G} be a representation of G as asymptotically nonexpansive type mappings of C into itself such that the common fixed point set F(J) of J in C is nonempty. It is proved that ∩s∈G co {T ts x:t∈G}∩F(J) is nonempty for each x ∈ C if and only if there exists a nonexpansive retraction P of C onto F(J) such that PT s=T sP=P for all s∈G and P(x) is in the closed convex hull of {T sx:s∈G}, x∈C . This result shows that many key conditions in [1-4, 9, 12-15 ] are not necessary.
