Returning crop straw into the soil is an important practice to balance biogenic and bioavailable silicon(Si)pool in paddy,which is crucial for the healthy growth of rice.However,owing to little knowledge about soil mi...Returning crop straw into the soil is an important practice to balance biogenic and bioavailable silicon(Si)pool in paddy,which is crucial for the healthy growth of rice.However,owing to little knowledge about soil microbial communities responsible for straw degradation,how straw return affects Si bioavailability,its uptake,and rice yield remains elusive.Herein,we investigate the change of soil Si fractions and microbial community in a 39-year-old paddy field amended by a long-term straw return.Results show that rice straw return significantly increased soil bioavailable Si and rice yield from 29.9%to 61.6%and from 14.5%to 23.6%,respectively,when compared to NPK fertilization alone.Straw return significantly altered soil microbial community abundance.Acidobacteria was positively and significantly related to amorphous Si,while Rokubacteria at phylum level,Deltaproteobacteria,and Holophagae at class level was negatively and significantly related to organic matter adsorbed and Fe/Mn-oxide-combined Si in soils.Redundancy analysis of their correlations further demonstrated that Si status significantly explained 12%of soil bacterial community variation.These findings suggest that soil bacteria community and diversity interact with Si mobility by altering its transformation,thus resulting in the balance of various nutrient sources to drive biological Si cycle in agroecosystem.展开更多
Silicon shows no variation in its chemical valence in nature and exists mainlyin the form of silicon-oxygen tetrahedra, so very small silicon isotope thermodynamic fractionation occurs and the resultant silicon isotop...Silicon shows no variation in its chemical valence in nature and exists mainlyin the form of silicon-oxygen tetrahedra, so very small silicon isotope thermodynamic fractionation occurs and the resultant silicon isotope variation is limited. Dynamic fractionation of Si isotopes during precipitation of SiO2 from a solution is a main factor leadingto substantial variations in silicon isotopes in nature. In this experimental study, wedetermined the dynamic fractionation factor a for silicon isotopes during precipitationof SiO2 from the solution. And in combination of α, a theoretical explanation is presented of the considerably low δ30Si values of black smokers on modern seafloor, Archeanbanded magnetite-quartzite and clay minrals of weahering origin, and of clearly highδ30Si values of siliceous rocks in shallow-sea carbonate platforms.展开更多
Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from f...Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from four typical alkali-rich porphyry deposits based on the dynamic fractionation principle of silicon isotope. The study shows that the ore materials should originate mainly from alkali-rich magmas, together with silicon-rich mineralizing fluids. The process of mineralization was completed by auto-metasomatism, i.e. silicon-rich mineralizing fluids (including alkali-rich porphyry and wall-rock strata) replaced and altered the country rocks and contaminated with crustal rocks during the crystallization of alkali-rich magmas. Such a process is essentially the continuance of the metasomatism of mantle fluids in crust's mineralization. This provides important evidence of silicon isotopic geochemistry for better understanding the mineralization of the Cenozoic alkali-rich porphyry polymetallic deposits展开更多
A new method for determination of trace silicon in high purity lanthanum oxide by using electrothermal vaporization (ETV) ICP AES with polytetrafluoroethylene(PTFE) slurry as a fluorinating reagent has been proposed...A new method for determination of trace silicon in high purity lanthanum oxide by using electrothermal vaporization (ETV) ICP AES with polytetrafluoroethylene(PTFE) slurry as a fluorinating reagent has been proposed. Under the optimized experimental conditions, the fluorination reactions of analyte(Si) and matrix(La) with PTFE in the graphite furnace took place at high temperature, and the fractional volatilily between Si and La was observed. Based on this principle the matrix interference could be eliminated. The detection limit of Si was 4.0 μg·L -1 , and the RSD was 3.4%( C =0.2 mg·L -1 , n =10). The procedure proposed has been applied successfully to determine trace Si in La 2O 3 without any chemical pre treatment.展开更多
In this paper, an analytical model to investigate the parametric amplification （PA） and the PA ＋ stimulated Raman scattering （SRS） in silicon waveguides is put forward. When two pump signals are employed, the PA ...In this paper, an analytical model to investigate the parametric amplification （PA） and the PA ＋ stimulated Raman scattering （SRS） in silicon waveguides is put forward. When two pump signals are employed, the PA bandwidth of the probe signal is so large that the Raman contribution has to be considered. When Raman contribution fraction f is set to be 0, only the PA occurs to amplify the probe signal, and when f is set to be 0.043, the PA and the SRS amplify the probe signal at the same time. The signal amplifications of both single and dual pump schemes are investigated by using this model. With this model, three main affecting factors, i.e., zero dispersion wavelength （ZDWL）, third-order dispersion （TOD）, and fourth-order dispersion （FOD）, are discussed in detail.展开更多
We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with...We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with boron on the n-type Si (100) surface. This longitudinal quantum conductance staircase, Gxx, is revealed by the voltage applied to the Hall contacts, Vxy, to a maximum of 4e2/h. In addition to the standard plateau, 2e2/h, the variations of the Vxy voltage appear to exhibit the fractional forms of the quantum conductance staircase with the plateaus and steps that bring into correlation respectively with the odd and even fractional values.展开更多
基金Fundamental Research Funds for Central Non-profit Scientific Institution(Nos.1610132019011,1610132020012)the National Key Research and Development Program of China(Nos.2016YFD0800707,2016YFD0200109).
文摘Returning crop straw into the soil is an important practice to balance biogenic and bioavailable silicon(Si)pool in paddy,which is crucial for the healthy growth of rice.However,owing to little knowledge about soil microbial communities responsible for straw degradation,how straw return affects Si bioavailability,its uptake,and rice yield remains elusive.Herein,we investigate the change of soil Si fractions and microbial community in a 39-year-old paddy field amended by a long-term straw return.Results show that rice straw return significantly increased soil bioavailable Si and rice yield from 29.9%to 61.6%and from 14.5%to 23.6%,respectively,when compared to NPK fertilization alone.Straw return significantly altered soil microbial community abundance.Acidobacteria was positively and significantly related to amorphous Si,while Rokubacteria at phylum level,Deltaproteobacteria,and Holophagae at class level was negatively and significantly related to organic matter adsorbed and Fe/Mn-oxide-combined Si in soils.Redundancy analysis of their correlations further demonstrated that Si status significantly explained 12%of soil bacterial community variation.These findings suggest that soil bacteria community and diversity interact with Si mobility by altering its transformation,thus resulting in the balance of various nutrient sources to drive biological Si cycle in agroecosystem.
文摘Silicon shows no variation in its chemical valence in nature and exists mainlyin the form of silicon-oxygen tetrahedra, so very small silicon isotope thermodynamic fractionation occurs and the resultant silicon isotope variation is limited. Dynamic fractionation of Si isotopes during precipitation of SiO2 from a solution is a main factor leadingto substantial variations in silicon isotopes in nature. In this experimental study, wedetermined the dynamic fractionation factor a for silicon isotopes during precipitationof SiO2 from the solution. And in combination of α, a theoretical explanation is presented of the considerably low δ30Si values of black smokers on modern seafloor, Archeanbanded magnetite-quartzite and clay minrals of weahering origin, and of clearly highδ30Si values of siliceous rocks in shallow-sea carbonate platforms.
文摘Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from four typical alkali-rich porphyry deposits based on the dynamic fractionation principle of silicon isotope. The study shows that the ore materials should originate mainly from alkali-rich magmas, together with silicon-rich mineralizing fluids. The process of mineralization was completed by auto-metasomatism, i.e. silicon-rich mineralizing fluids (including alkali-rich porphyry and wall-rock strata) replaced and altered the country rocks and contaminated with crustal rocks during the crystallization of alkali-rich magmas. Such a process is essentially the continuance of the metasomatism of mantle fluids in crust's mineralization. This provides important evidence of silicon isotopic geochemistry for better understanding the mineralization of the Cenozoic alkali-rich porphyry polymetallic deposits
文摘A new method for determination of trace silicon in high purity lanthanum oxide by using electrothermal vaporization (ETV) ICP AES with polytetrafluoroethylene(PTFE) slurry as a fluorinating reagent has been proposed. Under the optimized experimental conditions, the fluorination reactions of analyte(Si) and matrix(La) with PTFE in the graphite furnace took place at high temperature, and the fractional volatilily between Si and La was observed. Based on this principle the matrix interference could be eliminated. The detection limit of Si was 4.0 μg·L -1 , and the RSD was 3.4%( C =0.2 mg·L -1 , n =10). The procedure proposed has been applied successfully to determine trace Si in La 2O 3 without any chemical pre treatment.
基金Project supported by the National Basic Research Program of China (Grant No. 2010CB327605)the Discipline Co-construction Project of Beijing Municipal Commission of Education, China (Grant No. YB20081001301)the Fundamental Research Funds for Central Universities, China (Grant No. 2011RC008)
文摘In this paper, an analytical model to investigate the parametric amplification （PA） and the PA ＋ stimulated Raman scattering （SRS） in silicon waveguides is put forward. When two pump signals are employed, the PA bandwidth of the probe signal is so large that the Raman contribution has to be considered. When Raman contribution fraction f is set to be 0, only the PA occurs to amplify the probe signal, and when f is set to be 0.043, the PA and the SRS amplify the probe signal at the same time. The signal amplifications of both single and dual pump schemes are investigated by using this model. With this model, three main affecting factors, i.e., zero dispersion wavelength （ZDWL）, third-order dispersion （TOD）, and fourth-order dispersion （FOD）, are discussed in detail.
文摘We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with boron on the n-type Si (100) surface. This longitudinal quantum conductance staircase, Gxx, is revealed by the voltage applied to the Hall contacts, Vxy, to a maximum of 4e2/h. In addition to the standard plateau, 2e2/h, the variations of the Vxy voltage appear to exhibit the fractional forms of the quantum conductance staircase with the plateaus and steps that bring into correlation respectively with the odd and even fractional values.
