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Phosphate-Solubilizing and -Mineralizing Abilities of Bacteria Isolated from Soils

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Pedosphere 2008年第4期18卷 515-523页

作者： TAO guang-Can TIAN Shu-Jun CAI Miao-Ying xie guang-Hui Laboratory of Energy Crops College of Agronomy and Biotechnology China Agricultural University Beijing 100094 （China）. Institute of Microbiology Chinese Academy of Sciences Beijing 100080 （China）

Microorganisms capable of solubilizing and mineralizing phosphorus （P） pools in soils are considered vital in promoting P bioavallability. The study was conducted to screen and isolate inorganic P-solubilizing bacteria （IPSB） and organic P-mineralizing bacteria （OPMB） in soils taken from subtropical flooded and temperate non-flooded soils, and to compare inorganic P-solubilizing and organic P-solubilizing abilities between IPSB and OPMB. Ten OPMB strains were isolated and identified as Bacillus cereus and Bacillus megaterium, and five IPSB strains as B. megaterium, Burkholderia caryophyUi, Pseudomonas cichorii, and Pseudomonas syringae. P-solubilizing and -mineralizing abilities of the strains were measured using the methods taking cellular P into account. The IPSB strains exhibited inorganic P-solubilizing abilities ranging between 25.4-41.7 μg P mL^-1 and organic P-mineralizing abilities between 8.2-17.8μg P mL^-1. Each of the OPMB strains also exhibited both solubilizing and mineralizing abilities varying from 4.4 to 26.5 μg P mL^-1 and from 13.8 to 62.8 μg P mL^-1, respectively. For both IPSB and OPMB strains, most of the P mineralized from the organic P source was incorporated into the bacterial cells as cellular P. A significantly negative linear correlation （P 〈 0.05） was found between culture pH and P solubilized from inorganic P by OPMB strains. The results suggested that P solubilization and mineralization could coexist in the same bacterial strain.

关键词： Bacillus sp. Burkholderia sp. inorganic phosphate-solubilizing bacteria organic phosphorus-mineralizing bacteria Pseudomonas sp.

Infrared Polarization and Beaming Effect for BL Lac Objects

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Chinese Physics Letters 2001年第5期18卷 708-710页

作者： MEI Dong-Cheng xie guang-Zhong Yunnan Astronomical Observatory Chinese Academy of SciencesKunming 650011 The National Astronomical Observatories Chinese Academy of Sciences Yunnan Astrophysics Center Yunnan UniversityKunming 650091

With the idea of the beaming models,we derive a relation between the observed polarization and Doppler-corrected magnitude,that is,the observed polarization is in anti-correlation with the Doppler-corrected *** use of the infrared data observed simultaneously by Impey et al.[***.200(1982)19;209(1984)245]and Holmes et al.[ibid.210(1984)961]we found that(1)there is a significant correlation between the observed maximum polarization and Doppler-corrected magnitude but the polarization is not in anti-correlation with the Doppler corrected magnitude;(2)the maximum infrared polarization is strongly correlated with the maximum optical *** conclusion is that the infrared polarization depends only on the degree of ordering of the magnetic field in the synchotron emission regions and not on the beaming *** infrared and optical emissions originate from the synchrotron radiation.

关键词： polarization optical Soc

Modeling and analysis of passive dynamic bipedal walking with segmented feet and compliant joints

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Acta Mechanica Sinica 2012年第5期28卷 1457-1465页

作者： Yan Huang Qi-Ning Wang Yue Gao guang-Ming xie Intelligent Control Laboratory College of EngineeringPeking University

Passive dynamic walking has been developed as a possible explanation for the efficiency of the human gait. This paper presents a passive dynamic walking model with segmented feet, which makes the bipedal walking gait more close to natural human-like gait. The proposed model extends the simplest walking model with the addition of fiat feet and torsional spring based compliance on ankle joints and toe joints, to achieve stable walking on a slope driven by gravity. The push-off phase includes foot rotations around the toe joint and around the toe tip, which shows a great resemblance to human normal walking. This paper investigates the effects of the segmented foot structure on bipedal walking in simulations. The model achieves satisfactory walking results on even or uneven slopes.

关键词： Passive dynamic walking · Segmented feet·Compliant joints· Bipeds

A Close Correlation between the Spectral Lags and Redshifts of Gamma-Ray Bursts

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Chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 81-86页

作者： Ting-Feng Yi guang-Zhong xie Fu-Wen Zhang Physics Department Yunnan University Kunming 650091 National Astronomical Observatories/-Yunnan Observatory Chinese Academy of Sciences Kunming 650011 Yunnan Astronomical Center Yunnan University Kunming 650091 Graduate School of Chinese Academy of Sciences Beijing 100049

Based on nine BATSE GRBs with known redshifts, we found that the maximum spectral lag of all the pulses in a gamma-ray burst （GRB） appears to be anti-correlated with the redshift of the burst. In order to confirm this finding, we analyzed 10 GRBs detected by HETE-2 with known redshifts and found a similar relation. Using the relation, we estimated the redshifts of 878 long GRBs in the BATSE catalog, then we investigated the distributions of the redshifts and 869 Eiso of these GRBs. The distribution of the estimated redshifts is concentrated at z = 1.4 and the distribution of Eiso peaks at 10^52.5 erg. The underlying physics of the correlation is unclear at present.

关键词： gamma-rays bursts - gamma-rays observations - methods statistical

Microstructural Instability of an Experimental Nickel-Based Single-Crystal Superalloy

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1433-1441页

作者： Bin Yin guang xie Xiangwei Jiang Shaohua Zhang Wei Zheng Langhong Lou Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Microstructural instability with the precipitation of topologically close-packed(TCP)phases of an experimental nickel-based single-crystal superalloy has been investigated.A significant amount of σ phases are distinguished in the interdendritic region of the as-cast samples after thermal exposure at 900℃ for 1000 ***σphases are preferentially precipitated at the periphery of coarse γ/γ′eutectic,and their morphological evolution from needles to granules is *** analysis suggests that the local segregation of Cr and Ti at the periphery of coarse γ/γ′eutectic accounts for the formation ofσphases in the as-cast *** heat treatment with low solution temperature and short holding time,the dendritic segregation of alloying elements(i.e.,W,Re,Ti and Ta)and the volume fraction of γ′phase in the interdendritic region are similar to that of the as-cast ***,no TCP phases are present in the interdendritic region of the heat-treated samples after thermal exposure,which is primarily ascribed to the elimination of local segregation of Cr and Ti near the coarse γ/γ′***,small quantities ofμphases are precipitated in the secondary dendrite arm near the interdendritic region after thermal exposure,due to the increased volume fraction ofγ′phase and the concomitant enrichment of W and Re in theγmatrix.

关键词： Nickel-based single-crystal superalloy Topologically close-packed(TCP)phases Segregation Eutectic

The mobility improvement of organic thin film transistors by introducing Zn O-nanrods as an zctive layer

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Science China(Technological Sciences) 2016年第5期59卷 714-720页

作者： xie Tao xie guang Zhong DU Hong Fei YE Zong Biao SU Yuan Jie CHEN Yu Yan School of Optoelectronic Information State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China (UESTC)

Organic thin film transistors(OTFTs) based on poly(3-hexylthiophene)(P3HT)/Zinc oxide(ZnO) nanorods composite films as the active layers were prepared by spray-coating process. The OTFTs with P3HT/ZnO-nanorods composite films owned higher carriers mobility than the OTFT based on pure P3 HT. It can be found that the mobility of OTFTs increased by 135% due to ZnO-nanorods doping. This was attributed to the improvement of the P3 HT crystallinity and the optimization of polymer chains orientation. Meanwhile, because of the distinction of work function between P3 HT and ZnO, the majority carriers would accumulate on either side of the P3HT-ZnO interface which benefited carrier transfer. The influence on the mobility of composite film was studied. In addition, the threshold voltage of devices changed positively with the increase of ZnO-nanorods due to the decrease of electrostatic potential for P3HT/ZnO-nanorods composite films. The effect could be explained by the energy level theory of semiconductor.

关键词： P3HT ZnO-nanorods composite film OTFT

Methyl and methane elimination in the gas phase reaction of zirconium atom with 2-butyne:A DFT study

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Chinese Chemical Letters 2010年第12期21卷 1501-1504页

作者： Tao Hong Li Chuan Ming Wang Xiao guang xie Department of Chemistry Southwest Forestry University Kunming 650224 China Department of Biology Honghe University Menzi 661100 China Department of Chemistry Yunnan University Kunming 650091 China

The mechanisms for CH3- and CH_4-elimination in the gas phase reaction of ground-state Zr with 2-butyne has been investigated in detail using B3LYP *** the elimination of CH3,two mechanisms which are similar to those previously found for the reactions of Y and Zr with propyne are *** mechanism for the elimination of CH_4 was revealed as：Zr ＋ CH3C≡CCH_3→π-complex→TS（H-migration）→HZr-（H2CCC）-CH3→TS（C-C insertion）→（H2CCC）-HZr-CH3→TS（H-migration）→CH4＋ ZrC3H2.

关键词： Mechanism Zirconium 2-Butyne B3LYP

A theoretical study on the water-mediated asynchronous addition between urea and formaldehyde

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Chinese Chemical Letters 2013年第1期24卷 85-88页

作者： Tao-Hong Li Xiao-guang xie Guan-Ben Du College of Wood Science and Technology Nanjing Forestry University Faculty of Chemistry Southwest Forestry University Department of Chemistry Yunnan Univerisity

The reaction between urea and formaldehyde in water solution was theoretically investigated by using B3LYP and MP2 methods. It was found that the addition of the nitrogen atom in urea to the carbonyl group in formaldehyde precedes the proton transfer and the proton migration from water to the carbonyl group occurs before the proton abstraction from the nitrogen. With one or two water molecules involved in the TS, the activation energy barrier is lowered compared to the TS of the mechanism with no water participation. The energy change along the reaction coordinate clearly shows that a zwitterionic-like intermediate does not exist on the PES. The reaction between urea and formaldehyde occurs in a concerted mechanism but with asynchronous characters, This is different from the stepwise mechanism recently found for the amination reactions of formaldehyde.

关键词： Urea Formaldehyde Water-mediated Asynchronous Addition

The effect of waist twisting on walking speed of an amphibious salamander like robot

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Acta Mechanica Sinica 2016年第3期32卷 546-550页

作者： Xin-Yan Yin Li-Chao Jia Chen Wang guang-Ming xie Intelligent Control Laboratory College of EngineeringPeking University Key State Laboratory for Turbulence & Complex Systems College of Engineering Peking University

Amphibious salamanders often swing their waist to coordinate quadruped walking in order to improve their crawling speed. A robot with a swing waist joint, like an amphibious salamander, is used to mimic this locomotion.A control method is designed to allow the robot to maintain the rotational speed of its legs continuous and avoid impact between its legs and the ground. An analytical expression is established between the amplitude of the waist joint and the step length. Further, an optimization amplitude is obtained corresponding to the maximum stride. The simulation results based on automatic dynamic analysis of mechanical systems（ADAMS） and physical experiments verify the rationality and validity of this expression.

关键词： Terrestrial locomotion Step length Waist twisting Walking speed