α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decrease...α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.展开更多
Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage...Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage of our quantum mechanical probabilistic and gravity to the issue of dark stuff in the universe. Our new horizon gives us a deeper insight, pointing to small black holes as candidates of dark stuff. We invoke the spooky nature of quantum physics which gets spookier to hold the universe together.展开更多
The ongoing discoveries and studies of novel topological quantum materials have become an emergent and important field of condensed matter physics. Recently, Hfres ignited renewed interest as a candidate of a novel to...The ongoing discoveries and studies of novel topological quantum materials have become an emergent and important field of condensed matter physics. Recently, Hfres ignited renewed interest as a candidate of a novel topological material. The single-layer Hffes is predicted to be a tWOldimensional large band gap topological insulator and can be stacked into a bulk that may host a temperatureldriven topological phase transition. Historically, Hfres attracted considerable interest for its anomalous transport properties characterized by a peculiar resistivity peak accompanied by a sign reversal carrier type. The origin of the transport anomaly remains under a hot debate. Here we report the first high-resolution laserlbased anglelresolved photoemission measurements on the temperature-dependent electronic structure in Hffes. Our results indicated that a temperature-induced Lifshitz transition occurs in Hffes, which provides a natural understanding on the origin of the transport anomaly in Hffe~. In addition, our observa- tions suggest that Hffes is a weak topological insulator that is located at the phase boundary between weak and strong topological insulators at very low temperature.展开更多
Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89： 06...Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89： 064603]. However, double β^＋ -decay （β^＋β^＋） with emission of both two positrons and two neutrinos has not been observed up to date. In this article, we pcrform a systematic analysis on the candidates of double β^＋-decay, based on the 2012 nuclear mass table. Eight nuclei are found to be the good candidates for double β^＋-decay and their half-lives are predicted according to the generalization of the systematic law to double β^＋-decay. As far as we know, there is no theoretical result on double β^＋-decay of nucleus ^154Dy and our result is the first prediction on this nucleus. This is also the first complete research on eight double β^＋-decay candidates based on the available data of nuclear masses. It is expected that the calculated half-lives of double β^＋-decay in this article will be useful for future experimental search of double β^＋-decay.展开更多
基金supported by the National Natural Science Foundation of China(51502221)~~
文摘α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.
文摘Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage of our quantum mechanical probabilistic and gravity to the issue of dark stuff in the universe. Our new horizon gives us a deeper insight, pointing to small black holes as candidates of dark stuff. We invoke the spooky nature of quantum physics which gets spookier to hold the universe together.
基金supported by the National Key Research and Development Program of China (2016YFA0300600)the National Natural Science Foundation of China(11574367)+1 种基金the National Basic Research Program of China (2013CB921700,2013CB921904 and 2015CB921300)the Strategic Priority Research Program(B) of the Chinese Academy of Sciences(XDB07020300)
文摘The ongoing discoveries and studies of novel topological quantum materials have become an emergent and important field of condensed matter physics. Recently, Hfres ignited renewed interest as a candidate of a novel topological material. The single-layer Hffes is predicted to be a tWOldimensional large band gap topological insulator and can be stacked into a bulk that may host a temperatureldriven topological phase transition. Historically, Hfres attracted considerable interest for its anomalous transport properties characterized by a peculiar resistivity peak accompanied by a sign reversal carrier type. The origin of the transport anomaly remains under a hot debate. Here we report the first high-resolution laserlbased anglelresolved photoemission measurements on the temperature-dependent electronic structure in Hffes. Our results indicated that a temperature-induced Lifshitz transition occurs in Hffes, which provides a natural understanding on the origin of the transport anomaly in Hffe~. In addition, our observa- tions suggest that Hffes is a weak topological insulator that is located at the phase boundary between weak and strong topological insulators at very low temperature.
基金supported by the National Natural Science Foundation of China(Grant Nos.11035001,10975072,11120101005,11175085 and11375086)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Nuclear double β^--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys Rev C, 2014, 89： 064603]. However, double β^＋ -decay （β^＋β^＋） with emission of both two positrons and two neutrinos has not been observed up to date. In this article, we pcrform a systematic analysis on the candidates of double β^＋-decay, based on the 2012 nuclear mass table. Eight nuclei are found to be the good candidates for double β^＋-decay and their half-lives are predicted according to the generalization of the systematic law to double β^＋-decay. As far as we know, there is no theoretical result on double β^＋-decay of nucleus ^154Dy and our result is the first prediction on this nucleus. This is also the first complete research on eight double β^＋-decay candidates based on the available data of nuclear masses. It is expected that the calculated half-lives of double β^＋-decay in this article will be useful for future experimental search of double β^＋-decay.
