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Cu/Pd-catalyzed borocarbonylative trifunctionalization of alkynes and allenes:synthesis ofβ-geminal-diboryl ketones

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Science China Chemistry 2021年第12期64卷 2142-2153页

作者： Yang Yuan Fu-Peng Wu Anke Spannenberg Xiao-Feng Wu Leibniz-Institut für Katalyse e.V.an der Universität Rostock Albert-Einstein-Straβe 29a18059RostockGermany Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China

Functionalized bisboryl compounds have recently emerged as a new class of synthetically useful building blocks in organic ***,we report an efficient strategy to synthesizeβ-geminal-diboryl ketones enabled by a Cu/Pd-catalyzed borocarbonylative trifunctionalization of readily available alkynes and *** reaction promises to be a useful method for the synthesis of functionalizedβ-geminal-diboryl ketones with broad functional group *** studies suggest that the reaction proceeds through borocarbonylation/hydroboration cascade of both alkynes and allenes.

关键词： carbonylation copper/palladium alkynes/allenes trifunctionalization β-geminal-diboryl ketones

Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

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chinese Journal of Oceanology and Limnology 2009年第2期27卷 383-388页

作者： K. K. I. U. Arunakumara 张学成 College of Marine Life Sciences Ocean University of China Department of Crop Science Faculty of AgricultureUniversity of Ruhuna

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉（0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.

关键词： growth pigment contents Synechocystis sp. PCC 6803 ultrastructure

Identification of the active sites and mechanism for partial methane oxidation to methanol over copper-exchanged CHA zeolites

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Science China Chemistry 2020年第6期63卷 850-859页

作者： Yu Mao P.Hu School of Chemistry and Chemical Engineering The Queen’s University of BelfastBelfastUK

To make methane a suitable energy carrier and transport less costly,it is an urgent and challenging task for us to convert methane to liquid under mild conditions *** this study,we explored partial methane oxidation to methanol by density functional theory(DFT)calculations using a hybrid functional(HSE06)with van der Waals(vdW)*** stabilities of different active sites over SSZ-13 and SAPO-34,two CHA type zeolites,are thoroughly investigated by ab initio molecular dynamics(AIMD)simulations and ab initio thermodynamics *** possible active sites,namely[CuOHCu]2+,[Cu(OH)2Cu]2+,[CuOCu]2+and[CuOH]+,are identified ***-to-methanol reaction mechanisms are further studied upon these most stable active sites,among which[CuOCu]2+and[CuOH]+are proved to be *** migration of species among zeolite pores are also discussed,which accounts for the activity on[CuOH]+*** concept may represent a more complete picture of catalytic reactions over zeolites in general.

关键词： DFT heterogeneous catalysis methane-to-methanol CHA zeolites

Helicity Amplitudes for Photoproduction of Baryons with J=1/2 and J^P=3/2^+

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Communications in Theoretical Physics 2015年第12期64卷 719-726页

作者：刘磊华 Institute for Theoretical Physics Spinoza Institute and the Center for Extreme Matter and Emergent PhenomenaUtrecht University

We derive the separate helicity amplitudes using the partial wave analysis in the process of pseudo-scalar meson *** J^P= 3/2^+,we find the amplitude is model *** to parity conservation,the general amplitude in the case of J^P=1/2 is *** prove this general amplitude corresponds to the situation of λ=-1 when adopting the circular ***,the formulas of scattering amplitudes involving the meson photoproduction with J^P= 3/2^+ are obtained from the chiral quark model.

关键词： parity partial wave analysis d function quark mode

Estimation of failure probability in braced excavation using Bayesian networks with integrated model updating

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Underground Space 2020年第4期5卷 315-323页

作者： Longxue He Yong Liu Sifeng Bi Li Wang Matteo Broggi Michael Beer Institute for Risk and Reliability Leibniz Universitat HannoverGermany State Key Laboratory of Water Resources and Hydropower Engineering Science Institute of Engineering Risk and Disaster PreventionWuhan UniversityChina School of Civil and Safety Engineering Dalian Jiaotong UniversityChina Institute for Risk and Uncertainty University of LiverpoolUK International Joint Research Center for Engineering Reliability and Stochastic Mechanics Tongji UniversityChina

A probabilistic model is proposed that uses observation data to estimate failure probabilities during *** model integrates a Bayesian network and distanced-based Bayesian model *** the network,the movement of a retaining wall is selected as the indicator of failure,and the observed ground surface settlement is used to update the soil *** responses of wall deflection and ground surface settlement are accurately predicted using finite element *** artificial neural network is employed to construct the response surface relationship using the aforementioned input *** proposed model effectively estimates the uncertainty of influential factors.A case study of a braced excavation is presented to demonstrate the feasibility of the proposed *** update results facilitate accurate estimates according to the target value,from which the corresponding probabilities of failure are *** proposed model enables failure probabilities to be determined with real-time result updating.

关键词： Failure probability Braced excavation Bayesian networks Stochastic model updating Sensitivity analysis

A random linear code based secure transmission scheme for wireless fading channels

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Science China(Information Sciences) 2017年第4期60卷 241-243页

作者： Lukman A.OLAWOYIN Nana ZHANG A.O.OLOYEDE Nasir FARUK Hongwen YANG Wireless Communication Center Beijing University of Posts and Telecommunications Department of Telecommunication Science University of Ilorin

Dear editor,Wireless transmissions are vulnerable to potential security threats such as eavesdropping and wiretapping since unauthorized reception is facilitated through wireless channels[1].Traditional system security is mainly implemented in the higher layers of the communication protocol stack,relying on authentication and cryptography[2].The recent researches explore security in the physical layer[3],which can help to protect the information

关键词： code length A random linear code based secure transmission scheme for wireless fading channels

Real-time Locally Optimal Schedule for Electric Vehicle Load via Diversity-maximization NSGA-II

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Journal of Modern Power Systems and Clean Energy 2021年第4期9卷 940-950页

作者： Hongqian Wei Jun Liang Chuanyue Li Youtong Zhang Low Emission Vehicle(Beijing Key Lab)Research Laboratory School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China School of Engineering Cardiff UniversityCardiffCF243AAU.K

As distributed energy storage equipments, electric vehicles (EVs) have great potential for applications in power systems. Meanwhile, reasonable optimization of the charging time of EVs can reduce the users’ expense. Thus, the schedule of the EV load requires multi-objective optimization. A diversity-maximization non-dominated sorting genetic algorithm (DM-NSGA)-II is developed to perform multi-objective optimization by considering the power load profile, the users’charging cost, and battery degradation. Furthermore, a real-time locally optimal schedule is adopted by utilizing a flexible time scale. The case study illustrates that the proposed DM-NSGA-II can prevent being trapped in a relatively limited region so as to diversify the optimal results and provide trade-off solutions to decision makers. The simulation analysis shows that the variable time scale can continuously involve the present EVs in the real-time optimization rather than rely on the forecasting data. The schedule of the EV load is more practical without the loss of accuracy.

关键词： Electric vehicle(EV) locally optimal schedule multi-objective optimization diversity maximization genetic algorithm

More efficient ground truth ROI image coding technique: implementation and wavelet based application analysis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 835-840页

作者： KUMARAYAPA Ajith Department of Electronics and Communication Engineering Harbin Institute of Technology Harbin 150001 China

In this paper, more efficient, low-complexity and reliable region of interest （ROI） image codec for compressing smooth low texture remote sensing images is proposed. We explore the efficiency of the modified RO! codec with respect to the selected set of convenient wavelet filters, which is a novel method. Such ROI coding experiment analysis representing low bit rate lossy to high quality lossless reconstruction with timing analysis is useful for improving remote sensing ground truth surveillance efficiency in terms of time and quality. The subjective [i.e. fair, five observer （HVS） evaluations using enhanced 3D picture view Hyper memory display technology] and the objective results revealed that for faster ground truth ROI coding applications, the Symlet-4 adaptation performs better than Biorthogonal 4.4 and Biorthogonal 6.8. However, the discrete Meyer wavelet adaptation is the best solution for delayed ROI image reconstructions.

关键词： Smooth low texture remote sensing (SLTRS) image Modified region of interest (ROI) image codec Wavelet filters Low bit rate (LBR). High bit rate (HBR). ROI coding

Experimental verification of the potential of superhydrophobic surfaces in reducing audible noise on HVAC overhead line conductors

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High Voltage 2022年第4期7卷 692-704页

作者： Xu Zhang Ian Cotton Qi Li Simon MRowland Christopher Emersic Chengxing Lian Wenyuan Li Department of Electrical and Electronic Engineering The University of ManchesterManchesterUK School of Electrical Engineering Chongqing UniversityChongqingChina

Overhead line conductors can generate audible noise across a wide frequency spectrum as a result of elevated electric fields at the conductor *** fields are enhanced by the presence of surface defects,insects,water drops and *** this paper,the impact of a superhydrophobic coating on the audible noise produced by an overhead line conductor is *** levels from a conductor coated with a superhydrophobic coating were compared to those from a bare conductor in a semi-anechoic *** conductors were energised at voltages to provide surface electric fields ranging from 6 kV/cm to 21 kV/cm(rms).With a continuous water spray system depositing droplets on the conductor surface,the frequency domain sound pressure level,overall sound pressure levels and corona discharge magnitude were *** is demonstrated that the use of a superhydrophobic coating reduced audible noise levels and corona discharge magnitude,especially at electric fields above 14 kV/*** image analysis suggests that the water drop size distribution and the position of surface droplets on the conductor circumference play an important role in the magnitude of audible noise.

关键词： coating surface potential