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PTCs promoted biphasic oxidation of ethylbenzene catalyzed by NHPI and CoSPc

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Chinese Chemical Letters 2012年第8期23卷 895-898页

作者： Yu Lu Zhou sha sha Lin Dao Hong Xia Yu Zhi Xiang College of Science State Key Laboratory of Heavy OilChina University of PetroleumQingdao 266580China

An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid-liquid heterogeneous system. Experimental results showed that the reaction performed well facilitated by PTCs at multigrams material level, under which the conversion rate of ethylbenzene and the selectivity of acetophenone reached 60.6% and 95.2% after 0.5 h of reaction in oxygen atmosphere. An oxidation process was orooosed at the end of this oaoer.

关键词： Ethylbenzene Aerobic oxidation NHPI CoSPc PTC

Microstructural evolution and mechanical properties of Nb-Si-Cr ternary alloys with a tri-phase Nb/Nb5Si3/Cr2Nb microstructure fabricated by spark plasma sintering

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Progress in Natural Science:Materials International 2018年第5期28卷 626-634页

作者： shasha Zhang Wei Liu Jiangbo sha School of Materials Science and Engineering Beihang University Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials

In this work,pure Nb,Nb;Si;and Laves Cr;Nb compound powders were used as raw materials to prepare Nb-SiCr ternary alloys by spark plasma sintering（SPS）.A comprehensive estimation of the microstructure and properties,including room temperature fracture toughness,high temperature strength and oxidation resistance,of the Nb-Si-Cr ternary alloys as a function of the Nb/Nb;Si;/Cr;Nb phase volume fraction combinations was *** results showed that Nb-Si-Cr ternary samples with the relative density larger than 98.42% were obtained by SPS processing,and the samples all consisted of Nb,Nb;Si;and Cr;Nb phases that were distributed *** fracture toughness K;of the Nb/Nb;Si;/Cr;Nb microstructure,which was dominated by the Nb phase,naturally increased with the Nb *** expected,the room-temperature Vickers hardness and the high-temperature strength of the bulk alloys increased monotonically with the increasing of the stiffening Nb;Si;***,the binary Cr;Nb phase played a positive role in the high temperature strength and oxidation ***,the fracture modes of the typical Nb/Nb;Si;/Cr;Nb microstructures under bending and compression conditions at room and high temperatures as well as the oxidation mechanism are described and discussed.

关键词： Nb-Si Alloy Spark Plasma Sintering(SPS) Phase Fraction Fracture Toughness High-Temperature Strength

A new impedance and robust adaptive inverse control approach for a teleoperation system with varying time delay

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Science China(Technological Sciences) 2009年第9期52卷 2629-2643页

作者： Mokhtar sha SADEGHI Hamid Reza MOMENI Electrical and Electronic Engineering Department Shiraz University of TechnologyShiraz Iran Electrical Engineering Department Faculty of Engineering Tarbiat Modares UniversityTehran Iran

This paper presents a new robust adaptive inverse control approach for a force-reflecting teleoperation system with varying time delay. First,an impedance control is designed for the master robot. Second,an adaptive inverse control is proposed for the slave robot. Finally,the slave side controller is modified such that the robust stability and performance are achieved. In addition,robust stability analysis has been performed and optimal behavior is ensured by using standard characteristic polynomials. It is shown that despite of presence of randomly-varying time delay,the proposed control algorithm compensates the position drifts efficiently. Demonstrable simulation studies confirm the effectiveness of the proposed control system and its advantages over the existing sliding mode control strategies.

关键词： teleoperation bilateral force feedback adaptive inverse control time delay system

MP-WFRFT and Constellation Scrambling Based Physical Layer Security System

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China Communications 2016年第2期13卷 138-145页

作者： FANG Xiaojie sha Xuejun LI Yue Communication Research Center Harbin Institute of Technology

In this paper, a multiple parameters weighted fractional Fourier transform(MPWFRFT) and constellation scrambling(CS) method based physical layer(PHY) security system is proposed. The proposed scheme is executed by two steps. In the first step, MPWFRFT, implemented as the constellation beguiling(CB) method, is applied to change the signal's identity. In the second step the additional pseudo random phase information, regarded as the encryption key, is attached to the original signal to enhance the security. Typically, the pseudo random phase information can be removed effectively by the legitimate receiver. In contrast to the cryptography based encryption algorithms and the conventional PHY secrecy techniques, the main contribution of the proposed scheme is concentrated on the variation in signal's characteristics. Simulation results show that the proposed scheme can prevent the exchanging signal from eavesdroppers' classifi cation or inception. Moreover, the proposed scheme can guarantee the BER performance at a tolerate increasing in computational complexity for the legitimate receivers.

关键词： weighted fractional Fourier transform(WFRFT) physical layer (PHY) security secrecycapacity

Effects of long-term fertilization on oxidizable organic carbon fractions on the Loess Plateau,China

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Journal of Arid Land 2016年第4期8卷 579-590页

作者： DING shaonan XUE sha LIU Guobin College of Natural Resources and Environment Northwest A&F University Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources

The effects of long-term fertilization on pools of soil organic carbon （SOC） have been well studied, but limited information is available on the oxidizable organic carbon （OOC） fractions, especially for the Loess Plateau in China. We evaluated the effects of a 15-year fertilization on the OOC fractions （F1, F2, F3 and F4） in the 0-20 and 20-40 cm soil layers in flat farmland under nine treatments （N （nitrogen, urea）, P （phosphorus, monocalcium phosphate）, M （organic fertilizer, composted sheep manure）, N＋P （NP）, M＋N （MN）, M＋P （MP）, M＋N＋P （MNP）, CK （control, no fertilizer） and bare land （BL, no crops or fertilizer））. SOC content increased more markedly in the treatment containing manure than in those with inorganic fertilizers alone. F1, F2, F4 and F3 accounted for 47%, 27%, 18% and 8% of total organic carbon, respectively. F1 was a more sensitive index than the other C fractions in the sensitivity index （SI） analysis. F1 and F2 were highly correlated with total nitrogen （TN） and available nitrogen （AN）, F3 was negatively correlated with pH and F4 was correlated with TN. A cluster analysis showed that the treatments containing manure formed one group, and the other treatments formed another group, which indicated the different effects of fertilization on soil properties. Long-term fertilization with inorganic fertilizer increased the F4 fraction while manure fertilizer not only increased labile fractions （F1） in a short time, but also increased passive fraction （F4） over a longer term. The mixed fertilizer mainly affected F3 fraction. The study demonstrated that manure fertilizer was recommended to use in the farmland on the Loess Plateau for the long-term sustainability of agriculture.

关键词： long-term fertilization oxidizable organic carbon fractions farmland soil Loess Plateau

Symmetry theories of Hamiltonian systems with fractional derivatives

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Science China(Physics,Mechanics & Astronomy) 2011年第10期54卷 1847-1853页

作者： ZHOU sha FU Hao FU JingLi Institute of Mathematical Physics Zhejiang Sci-Tech University Hangzhou 310018 China China Jingye Engineering Corporation Limited Shenzhen Branch Shenzhen 518054 China

The Noether and Lie symmetries as well as the conserved quantities of Hamiltonian system with fractional derivatives are es-tablished. The definitions and criteria for the fractional symmetrical transformations and quasi-symmetrical transformations inthe Noether sense of Hamiltonian system are first discussed. Then, using the invariance of Hamiltonian action under the infini-tesimal transformations with respect to time, generalized coordinates and generalized momentums, the fractional Noethertheorem of the system is obtained. Further, the Lie symmetry and conserved quantity of the system are acquired. Two exam-ples are presented to illustrate the application of the results.

关键词： symmetry conserved quantity Hamiltonian system fractional derivative

Premature Tapetum Degeneration: a Major Cause of Abortive Pollen Development in Photoperiod Sensitive Genic Male Sterility in Rice

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Journal of Integrative Plant Biology 2009年第8期51卷 774-781页

作者： Yinlian Shi sha Zhao Jialing Yao College of Life Science and Technology Huazhong Agricultural University Wuhan 430070 China

Photoperiod-sensitive genic male-sterile （PSGMS） rice （Oryza sativa L.）, a natural mutant found in the rice cultivar Nongken 58, is very useful for the development of hybrid rice cultivars. Despite its widespread use in breeding programs, the initial stage of the abortive development of PSGMS rice and the possible cytological mechanisms of pollen abortion have not been determined. In the present study, a systematic cytological comparison of the anther development of PSGMS rice with its normal fertile counterpart is conducted. The results show that pollen abortion in PSGMS rice first occurs before the pollen mother cell （PMC） stage, and continues during the entire process of pollen development until pollen degradation. The abortive process was closely associated with the abnormal behavior of the tapetum. Although tapetum degeneration in PSGMS rice initiates already at the PMC stage, it proceeds slowly and does not complete until the breakdown of the pollen. Such cytological observations were supported by the results of the TUNEL （TdT-mediated dUTP Nick End Labeling） assay, which detects DNA fragmentation resulting from programmed cell death （PCD）, indicating that the premature tapetum degeneration is in the process of PCD.

关键词： male-sterility Oryza sativa programmed cell death tapetum ultrastructure

Strategies for synthesizing non-bioaccumulable alternatives to PFOA and PFOS

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Chinese Chemical Letters 2015年第5期26卷 491-498页

作者： Min sha Ping Xing Biao Jiang School of Chemical Engineering Nanjing University of Science and Technology CAS Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of Sciences

This minireview describes the strategies for synthesis of fluorinated surfactants potentially non- bioaccumulable. Various strategies have been focused on （Ⅰ） reducing the length of the perfluorocarbon chain, （Ⅱ） introducing hereto atoms into the fluorocarbon chain, （Ⅲ） introducing branch （herein and after branch means the fluoro-carbon chain section is not straight）. In most cases, the surface tensions versus the surfactant concentrations have been assessed. These above strategies led to various highly fluorinated （perfluorinated or not perfluorinated） surfactants whose chemical changes enabled to obtain novel alternatives to perfluorooctanoic acid （PFOA） and perfluorooctane sulphonate （PFOS）.

关键词： Fluorinated surfactant PFOA PFOS Alternative Surface tension

OKMC simulation of vacancy-enhanced Cu solute segregation affected by temperature/irradiation in the Fe–Cu system

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Nuclear Science and Techniques 2022年第11期33卷 158-169页

作者： Zi-Qin Shen Jie Gao sha-sha Lv Liang Chen Dong-Yue Chen De-Sheng Ai Zheng-Cao Li Key Lab of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Nuclear and New Energy Institute Tsinghua UniversityBeijing 100084China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Beam Technology Ministry of EducationCollege of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Nuclear Engineering and Management The University of TokyoTokyo 113-8656Japan

The effects of annealing and irradiation on the evolution of Cu clusters in a-Fe are investigated using object kinetic Monte Carlo *** our model,vacancies act as carriers for chemical species via thermally activated diffusion jumps,thus playing an important role in solute *** the end of the Cu cluster evolution,the simulations of the average radius and number density of the clusters are consistent with the experimental data,which indicates that the proposed simulation model is applicable and *** the simulation of the annealing process,it is found that the evolution of the cluster size roughly follows the 1/2 time power law with the increase in radius during the growth phase and the 1/3 time power law during the coarsening *** addition,the main difference between neutron and ion irradiation is the growth and evolution process of the copper-vacancy *** aggregation of vacancy clusters under ion irradiation suppresses the migration and coarsening of the clusters,which ultimately leads to a smaller average radius of the copper *** proposed simulation model can supplement experimental analyses and provide a detailed evolution mechanism of vacancy-enhanced precipitation,thereby providing a foundation for other elemental precipitation research.

关键词： Object kinetic Monte Carlo Irradiation effect Solute segregation Reactor pressure vessel