Mo（CO）6 adsorption on the clean, oxygen-precovered and deeply oxidized Si（lll） surfaces was comparatively investigated by high-resolution electron energy loss spectroscopy. The downward vibrational frequency shift...Mo（CO）6 adsorption on the clean, oxygen-precovered and deeply oxidized Si（lll） surfaces was comparatively investigated by high-resolution electron energy loss spectroscopy. The downward vibrational frequency shift of the C-O stretching mode in adsorbed Mo（CO）6 illustrates that different interactions of adsorbed Mo（CO）6 occur on clean Si（111） and SiO2/Si（111） surfaces, weak on the former and strong on the latter. The strong interaction on SiO2/Si（111） might lead to the partial dissociation of Mo（CO）6, consequently the formation of molybdenum subcarbonyls. Therefore, employing Mo（CO）6 as the precursor, metallic molybdenum could be successfully deposited on the SiO2/Si（111） surface but not on the clean Si（111） surface. A portion of the deposited metallic molybdenum is transformed into the MoOa on the SiO2/Si（111） surface upon heating, and the evolved MoO3 finally desorbs from the substrate upon annealing at elevated temperatures.展开更多
Let A be a bornological quantum group and R a bornological algebra. If R is an essential A-module, then there is a unique extension to M（A）-module with 1x = x. There is a one-to-one corresponding relationship betwee...Let A be a bornological quantum group and R a bornological algebra. If R is an essential A-module, then there is a unique extension to M（A）-module with 1x = x. There is a one-to-one corresponding relationship between the actions of A and the coactions of . If R is a Galois object for A, then there exists a faithful δ-invariant functional on R. Moreover,the Galois objects also have modular properties such as algebraic quantum groups. By constructing the comultiplication Δ,counit ε, antipode S and invariant functional φ onR×R, R×R can be considered as a bornological quantum group.展开更多
Abstract In this work, ionization potentials and quantum effects of ls^2 np^2 P Rydberg states of lithium are calculated based on the calibrated quantum defect function. Energy levels and quantum defects for ls^2np^2P...Abstract In this work, ionization potentials and quantum effects of ls^2 np^2 P Rydberg states of lithium are calculated based on the calibrated quantum defect function. Energy levels and quantum defects for ls^2np^2P bound states and their adjacent continuum states are calculated with the R-matrix theory, and then the quantum defect function of the ls^2np （n ≥ 7） channel is obtained, which varies smoothly with the energy based on the quantum defect theory. The accurate quantum defect of the ls^2 7p^2P state derived from the experimental data is used to calibrate the original quantum defect function. The new function is used to calculate ionization potentials and quantum effects of ls^2np ^2P （n ≥ 7） Rydberg states. Present calculations are in agreement with recent experimental data in whole.展开更多
The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results sho...The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results show that the best separation results can be achieved when the pulp pH is 7.27 and 58.3 mg/L collector plus 6.67 mg/L depressant are added to the mixture.Products with 58.45%,62.78%and 63.72% iron grades can be achieved respectively when mass ratio of hematite to quartz is 2：3,1：1,and 3：2.The adsorption mechanism of ND13 on a quartz surface was investigated by zeta-potential and X-ray photoelectron spectroscopy measurements.The results reveal that electrostatic and hydrogen bonding adsorption take place between ND13 and the quartz surface,and that ND13 mainly interacts with the oxygen atoms on the quartz surface.展开更多
Nickel-based catalyst [N,N]NiBr2, in which [N,N] stands for N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine, shows high activity for ethylene polymerization in the presence of organoaluminum compounds under high et...Nickel-based catalyst [N,N]NiBr2, in which [N,N] stands for N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine, shows high activity for ethylene polymerization in the presence of organoaluminum compounds under high ethylene pressure to yield polyethylene characteristic of low molecular weight and highly branched chains. Toluene as the solvent is more in favor of catalyst activity, higher molecular weight and branched chains in polyethylene structure as compared to hexane solvent.展开更多
A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen (N) and sulfur (S) and canola (Brassica napus) and wheat (Triticum aestivum L. 'Biggar') N and ...A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen (N) and sulfur (S) and canola (Brassica napus) and wheat (Triticum aestivum L. 'Biggar') N and S uptake and yield in three Western Canadian soils. The suitability of one-hour burial with an anion exchange membrane (AEM) was assessed for its utility as a quick test of the available N:S balance in the soil. Canola and wheat were grown on a Luvisolic soil low in available S and on Brown and Black Chernozemic soils low in both available N and S, with different rates and combinations of N and S fertilizers applied. AEM burial was used to assess soil available nitrate and sulfate supply rates after fertilization. Dry matter yield and N and S concentrations in plant tissues were determined after 6 weeks of growth. The soil available N:S ratio determined by AEM burial closely reflected the relative supplies of available N and S as revealed in the N:S ratios of plant tissue dry matter. The highest yields were achieved where the available N:S ratio in soil and plant tissue ranged from 5 to 13. Thus, a one-hour burial of an AEM probe in the field may be a useful tool to quickly test if a balanced N and S supply is present in the soil for optimum crop yield.展开更多
In this paper, we present the decoupling bang-bang （BB） twin-born pulses to suppress the genera/deco- herence, both amplitude and phase decoherence, in a three-level atom in V- and Ξ-configurations. We give the exa...In this paper, we present the decoupling bang-bang （BB） twin-born pulses to suppress the genera/deco- herence, both amplitude and phase decoherence, in a three-level atom in V- and Ξ-configurations. We give the exact sequence of periodic twinborn pulses in such systems.展开更多
In this paper, we study a quantum anti-Zeno effect （QAZE） purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled reso...In this paper, we study a quantum anti-Zeno effect （QAZE） purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloeh electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove＇s singularities and the effects of the counter-rotating terms.展开更多
In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group （DMRG） algorithm. Effect of the intra-ehain next-neares...In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group （DMRG） algorithm. Effect of the intra-ehain next-nearest- neighbor （NNN） super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.展开更多
The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for ca...The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for calculating mass action concentration N_i of structural units in Ti-Al system based on the atom and molecule coexistence theory（AMCT）. Temperature dependence of the activity coefficients of Ti and Al in natural logarithmic form in the infinitely dilute solution（0x_（Ti）0.01） of Ti-Al binary melts was also determined from the calculated activity coefficients of Ti and Al at temperatures of 1973, 2073, 2173, and 2273 K. The standard molar Gibbs free energy change of dissolving pure liquid element i（l） for forming 1%（mass fraction） element i in Ti-Al binary melts further was deduced. With the aid of this model, meanwhile, the determined excess thermodynamic properties, such as the excess molar mixing Gibbs free energy/entropy/enthalpy were also calculated.展开更多
文摘基于最近发展的分子碎片共轭帽(molecular fractionation with conjugate caps,MFCC)方法,表皮生长因子受体(epidermal growth factor receptor,EGFR)与其抑制剂的相互作用能得以用完整的量子力学来计算,主要包括上市的Iressa[第一代美国食品及药物管理局(Food and Drug Administration,FDA)通过的药物]和4-苯胺基喹唑啉类抑制剂Tarceva(已上市)、CI-1033与EKI-785。对EGFR的完整体系(超过5 000个原子)与4-苯胺基喹唑啉类抑制剂之间的结合作用采用了量子力学计算方法。结合体系的量子能量计算,用Hartree-Fock与密度泛函理论(density functional theory,DFT)2种方法,EGFR与Tarceva之间的相互作用能基于它们两者复合物的晶体结构得到,而其他抑制剂与EGFR的相互作用能则通过分子对接软件预测的构型进行计算。利用MFCC方法,获得了量子相互作用能谱,清楚地给出了EGFR每个氨基酸片段与4-苯胺基喹唑啉类抑制剂之间的单个相互作用能。量子研究发现,4-苯胺基喹唑啉类抑制剂与EGFR的结合通过1个氢键和静电相互作用。Iressa、Tarceva、CI-1033、EKI-785与EGFR的结合能计算值分别为-40.23、-53.09、-33.92、-31.47kcal/mol(1cal=4.184J)。研究表明,Tarceva比第一代FDA通过的药物Iressa有更强的结合能力,而CI-1033、EKI-785则表现出一般的结合作用,另外,与MFCC计算的相互作用能谱相比,有一些相互作用在力场作用能谱中被明显高估。
文摘Mo（CO）6 adsorption on the clean, oxygen-precovered and deeply oxidized Si（lll） surfaces was comparatively investigated by high-resolution electron energy loss spectroscopy. The downward vibrational frequency shift of the C-O stretching mode in adsorbed Mo（CO）6 illustrates that different interactions of adsorbed Mo（CO）6 occur on clean Si（111） and SiO2/Si（111） surfaces, weak on the former and strong on the latter. The strong interaction on SiO2/Si（111） might lead to the partial dissociation of Mo（CO）6, consequently the formation of molybdenum subcarbonyls. Therefore, employing Mo（CO）6 as the precursor, metallic molybdenum could be successfully deposited on the SiO2/Si（111） surface but not on the clean Si（111） surface. A portion of the deposited metallic molybdenum is transformed into the MoOa on the SiO2/Si（111） surface upon heating, and the evolved MoO3 finally desorbs from the substrate upon annealing at elevated temperatures.
文摘Let A be a bornological quantum group and R a bornological algebra. If R is an essential A-module, then there is a unique extension to M（A）-module with 1x = x. There is a one-to-one corresponding relationship between the actions of A and the coactions of . If R is a Galois object for A, then there exists a faithful δ-invariant functional on R. Moreover,the Galois objects also have modular properties such as algebraic quantum groups. By constructing the comultiplication Δ,counit ε, antipode S and invariant functional φ onR×R, R×R can be considered as a bornological quantum group.
基金National Natural Science Foundation of China under Grant No.10404017the Basic Research Foundation of Beijing Institute of Technology
文摘Abstract In this work, ionization potentials and quantum effects of ls^2 np^2 P Rydberg states of lithium are calculated based on the calibrated quantum defect function. Energy levels and quantum defects for ls^2np^2P bound states and their adjacent continuum states are calculated with the R-matrix theory, and then the quantum defect function of the ls^2np （n ≥ 7） channel is obtained, which varies smoothly with the energy based on the quantum defect theory. The accurate quantum defect of the ls^2 7p^2P state derived from the experimental data is used to calibrate the original quantum defect function. The new function is used to calculate ionization potentials and quantum effects of ls^2np ^2P （n ≥ 7） Rydberg states. Present calculations are in agreement with recent experimental data in whole.
基金Financial support for this research provided by the National Key Technology Development and Research Programs of China(Nos. 2008BAB32B14 and 2008BAB31B03)
文摘The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results show that the best separation results can be achieved when the pulp pH is 7.27 and 58.3 mg/L collector plus 6.67 mg/L depressant are added to the mixture.Products with 58.45%,62.78%and 63.72% iron grades can be achieved respectively when mass ratio of hematite to quartz is 2：3,1：1,and 3：2.The adsorption mechanism of ND13 on a quartz surface was investigated by zeta-potential and X-ray photoelectron spectroscopy measurements.The results reveal that electrostatic and hydrogen bonding adsorption take place between ND13 and the quartz surface,and that ND13 mainly interacts with the oxygen atoms on the quartz surface.
文摘Nickel-based catalyst [N,N]NiBr2, in which [N,N] stands for N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine, shows high activity for ethylene polymerization in the presence of organoaluminum compounds under high ethylene pressure to yield polyethylene characteristic of low molecular weight and highly branched chains. Toluene as the solvent is more in favor of catalyst activity, higher molecular weight and branched chains in polyethylene structure as compared to hexane solvent.
基金Project supported by the Potash and Phosphate Institute of Canada (PPIC).
文摘A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen (N) and sulfur (S) and canola (Brassica napus) and wheat (Triticum aestivum L. 'Biggar') N and S uptake and yield in three Western Canadian soils. The suitability of one-hour burial with an anion exchange membrane (AEM) was assessed for its utility as a quick test of the available N:S balance in the soil. Canola and wheat were grown on a Luvisolic soil low in available S and on Brown and Black Chernozemic soils low in both available N and S, with different rates and combinations of N and S fertilizers applied. AEM burial was used to assess soil available nitrate and sulfate supply rates after fertilization. Dry matter yield and N and S concentrations in plant tissues were determined after 6 weeks of growth. The soil available N:S ratio determined by AEM burial closely reflected the relative supplies of available N and S as revealed in the N:S ratios of plant tissue dry matter. The highest yields were achieved where the available N:S ratio in soil and plant tissue ranged from 5 to 13. Thus, a one-hour burial of an AEM probe in the field may be a useful tool to quickly test if a balanced N and S supply is present in the soil for optimum crop yield.
基金The project supported by the National Fundamental Research Program under Grant No.2006CB921106National Natural Science Foundation of China under Grant Nos.10325521,60433050,and 60635040+1 种基金the SRFDP Program of Education Ministry of China under Grant No.20060003048the Key Project of the Ministry of Education of China under Grant No.306020
文摘In this paper, we present the decoupling bang-bang （BB） twin-born pulses to suppress the genera/deco- herence, both amplitude and phase decoherence, in a three-level atom in V- and Ξ-configurations. We give the exact sequence of periodic twinborn pulses in such systems.
基金Supported by the Natural Science Foundation of China under Grant Nos.10974209 and 10935010 the National 973 Program under Grant No.2006CB921205China Postdoctoral Science Foundation under Grant No.20100470584
文摘In this paper, we study a quantum anti-Zeno effect （QAZE） purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloeh electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove＇s singularities and the effects of the counter-rotating terms.
基金Supported by the Chinese National Science Foundation of China under Grant Nos.10874003,11074004,and 11047160Numerical Computation of This Work was Carried out on the Parallel Computer Cluster of Institute for Condensed Matter Physics(ICMP) at School of Physics,Peking University
文摘In this paper, we study the phase diagram of a frustrated spin ladder model by applying the bosonization technique and the density-matrix renormalization-group （DMRG） algorithm. Effect of the intra-ehain next-nearest- neighbor （NNN） super-exchange interaction is investigated in detail and the order parameters are calculated to detect the emergence of the dimerized phases. We find that the intra-chain NNN interaction plays a key role in inducing dimerized phases.
基金Project(U1560203)supported by the Joint Funds of the National Natural Science Foundation of ChinaProject(51274031)supported by the National Natural Science Foundation of China
文摘The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for calculating mass action concentration N_i of structural units in Ti-Al system based on the atom and molecule coexistence theory（AMCT）. Temperature dependence of the activity coefficients of Ti and Al in natural logarithmic form in the infinitely dilute solution（0x_（Ti）0.01） of Ti-Al binary melts was also determined from the calculated activity coefficients of Ti and Al at temperatures of 1973, 2073, 2173, and 2273 K. The standard molar Gibbs free energy change of dissolving pure liquid element i（l） for forming 1%（mass fraction） element i in Ti-Al binary melts further was deduced. With the aid of this model, meanwhile, the determined excess thermodynamic properties, such as the excess molar mixing Gibbs free energy/entropy/enthalpy were also calculated.
