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Four-coordinate disilyl cobalt(Ⅱ)complexes with NHC ligation:Synthesis,characterization,and reactivity

Chinese Chemical Letters 2024年第3期35卷 292-298页

作者： Lan Zhou Dongyang Wang Chengbo Yang Liang deng College of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China State key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

Silyl cobalt species are putative intermediates in cobalt-catalyzed transformations of ***,their reactivity has remained poorly *** here is the investigation on four-coordinate disilyl Co(Ⅱ)complexes with N-hetereocyclic carbene *** reactions of[(ICy)_(2)Co(vtms)](ICy=1,3-dicyclohexylimidazol-2-ylidene,vtms=vinyltrimethylsilane)with primary and secondary hydrosilanes(3 equiv.)furnish the four-coordinate disilyl complexes[trans-(ICy)_(2)Co(SiHRR')_(2)](SiHRR'=SiH_(2)Mes,1;SiH_(2)Ph,2;SiH_(2)Cy,3;SiHPh_(2),4;SiHEt_(2),5)in moderate to good *** structures of 1,2 and 4 were established by single-crystal X-ray *** magnetic susceptibility measurement and EPR spectroscopy indicate their low-spin nature(S=1/2).Reactivity studies on 4 led to the establishment of the conversions of 4 to the disilyl dihydride Co(Ⅲ)complex[k(THF)][(ICy)_(2)Co(H)_(2)(SiHPh_(2))_(2)]_n(6)and the fluorosilyl Co(Ⅱ)complex[(ICy)_(2)Co(THF)(SiFPh_(2))][BF_(4)](7)when 4 was treated with excess amount of k and AgBF_(4),respectively,in *** conversions hint at the high activity of low-valent and high-valent disilyl cobalt species[trans-(ICy)_(2)Co(SiHPh_(2))_(2)]^(1-)and[trans-(ICy)_(2)Co(SiHPh_(2))_(2)]^(2+).Complex 4 is reactive toward terminal alkynes,but inert toward alkenes and internal *** reactions of 4 with terminal alkynes CyC≡CH and Me_(3)SiC≡CH(3 equiv.)yield the Co(Ⅱ)complexes[(ICy)_(2)Co(C≡CCy)_(2)](8)and[(ICy)_(2)Co(C≡CSiMe_(3))((SiMe_(3))C=CH_(2))](9),respectively,along with H_(2)SiPh_(2)and alkynylsilanes RC≡CSiHPh_(2)(R=Cy,SiMe_(3)),whereas the reaction with 4-CF_(3)C_(6)H_(4)C≡CH(3 equiv.)produce[(ICy)_(2)Co(C≡CAr)((Ar)C=CH(SiHPh_(2))C=CHAr)](Ar=4-CF_(3)C_(6)H_(4))(10)and H_(2)SiPh_(2).These reactions are proposed to involveσ-bond metathesis reactions between alkyne C(sp)-H bonds and Co-Si bonds in *** 6–10 have been characterized by NMR spectroscopy,X-ray diffraction study,and elemental analysis.

关键词： Disilyl Cobalt N-Heterocyclic carbene Four-coordinate

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Air-tolerant direct reductive N-methylation of amines using formic acid via simple inorganic base catalysis

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Chinese Chemical Letters 2020年第1期31卷 111-114页

作者： Yan Huang Wei deng Bo-Lin Lin School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China School of Technology and Physical Science ShanghaiTech UniversityShanghai 201210China

The construction of N-methyl amine moieties is an important reaction that has found numerous *** of new methylation agents that are more environmentally benign than classical agents,such as iodomethane and methyl sulfate,is still highly ***,we report a convenient protocol for direct reductive N-methylation of amines using formic acid as the methylation agent via simple inorganic base *** present protocol operates under transition-metal-free and air-tolerant *** the catalyst,k2 HPO4,and the reductant,polymethylhydrosiloxane(PMHS),are cheap and easily separable from the crude reaction product *** investigations suggest that the reaction occur through the formation of an acetal inte rmediate followed by the C-N bond formation.

关键词： Air tolerant N-Methylation Formic acid Simple inorganic bas Transition-metal-free

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WOOD/PCM composite with enhanced energy storage density and anisotropic thermal conductivity

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Progress in Natural Science:Materials International 2022年第2期32卷 190-195页

作者： Hongfei Chen Jihang Xuan Qiaoling deng Yanfeng Gao School of Materials Science and Engineering Shanghai University

Phase change materials(PCMs) have great potential in energy-saving and environmental field due to their high latent *** deficiencies that restrict the application of PCMs are their poor thermal conductivity and liquid leakage after phase *** shoot these problems,a thermally-induced flexible WOOD/PCM composite with enhanced energy storage density and anisotropic thermal conductivity has been *** composite consisted of polyethylene glycol 6000(PEG6000),delignified balsa wood and boron nitride(BN).The results revealed that the melting enthalpy and freezing enthalpy of WOOD/PEG6000 composite were 209.3 J/g and214.9 J/g,which had an augment of about 8% comparing with pure *** adding 33 wt% BN to the composite,its thermal conductivity in the out-of-plane direction reached 0.96 W/(m·k),while the radial thermal conductivity was 0.36 W/(m·k).The controllable anisotropic thermal conductivity implies a good application in the environment where forced unidirectional heat dissipation is ***,the composite also shows excellent thermal induced flexibility,such as bending and compression,which is significant in reducing thermal contact resistance with substrates in *** work indicates that the prepared PCM composite has a great potential application in thermal energy storage and thermal management.

关键词： Phase change materials Nature wood structure High transformation enthalpy Anisotropic thermal conductivity Thermal induced flexibility

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Enhanced n-Type Thermoelectric Performance of Conjugated Polymers Based on an Indandione-Terminated Quinoidal Unit through Comonomer Optimization

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Chinese Journal of Chemistry 2023年第7期41卷 776-782页

作者： Tian Du Yingying Liu Yunfeng deng Yanhou Geng School of Materials Science and Engineering and Tianjin key Laboratory of Molecular Optoelectronic Science Tianjin UniversityandCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin300072 China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhouFujian350207 China

Comprehensive Summary Conjugated polymers(CPs)containing quinoidal units are promising in n-type organic thermoelectric materials because of their deep-positioned lowest unoccupied molecular orbital(LUMO)energy levels and planar conjugated ***,three CPs have been synthesized by copolymerizing an indandione-terminated quinoidal unit with bithiophene *** to the high electron affinity of the indandione-terminated quinoidal unit,all polymers showed deep LUMO energy levels below-4.10 *** electron-withdrawing substituents(F or CN)on the bithiophene comonomer can further downshift the LUMO energy *** a result,a more efficient n-doping process can be realized when employing 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine(N-DMBI)as the ***,the polymer with CN substituents delivered the best thermoelectric performance with a power factor of up to 2.14μW·m^(−1)·k^(−2),because it possessed the lowest LUMO energy level among the three *** work highlights that the modulation of LUMO energy level is an effective strategy to optimize the thermoelectric performance of CPs.

关键词： Conjugated polymers Quinoidal compounds Indandione n-Doping Organic thermoelectrics Organic electronics Electrontransfer Energyconversion

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Dynamic response of buildings under debris flow impact

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Journal of Mountain Science 2024年第5期21卷 1581-1597页

作者： LIU Huan FAN Xiaoyi TIAN Shujun deng Xin School of Mechanical and Electrical Engineering Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Geomatics Southwest Petroleum UniversityChengdu 610500China Housing and Urban-Rural Development Bureau of Mingshan District Ya’an 625100China Engineering Safety Assessment and Protection Research Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China

This study employs the smoothed particle hydrodynamics–finite element method(SPH–FEM) coupling numerical method to investigate the impact of debris flow on reinforced concrete(RC)-frame buildings. The methodology considers the variables of debris flow depth and velocity and introduces the intensity index IDV(IDV = DV) to evaluate three different levels of debris flow impact intensity. The primary focus of this study is to investigate the dynamic response and failure mechanism of RC-frame buildings under debris flow impact, including structural failure patterns, impact force and column displacement. The results show that under a highintensity impact, a gradual collapse process of the RCframe building can be observed, and the damage mode of the frame column reflects shear failure or plastic hinge failure mechanism. First, the longitudinal infill walls are damaged owing to their low out-of-plane flexural capacity;the critical failure intensity index IDV value is approximately 7.5 m2/s. The structure cannot withstand debris flows with an intensity index IDV greater than 16 m2/s, and it is recommended that the peak impact force should not exceed 2100 k N. The impact damage ability of debris flow on buildings mostly originates from the impact force of the frontal debris flow, with the impact force of the debris flow body being approximately 42% lower than that of the debris flow head. Finally, a five-level classification system for evaluating the damage status of buildings is proposed based on the numerical simulation and investigation results of the disaster site.

关键词： SPH–FEM method Debris flow Buildings The intensity index Dynamic response

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A Novel Hybrid Data Clustering Algorithm Based on Artificial Bee Colony Algorithm and k-Means

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Chinese Journal of Electronics 2015年第4期24卷 694-701页

作者： TRAN Dang Cong WU Zhijian WANG Zelin deng Changshou State key Laboratory of Software Engineering School of Computer Wuhan University Vietnam Academy of Science and Technology School of Information Science and Technology Jiujiang University

To improve the performance of k-means clustering algorithm, this paper presents a new hybrid approach of Enhanced artificial bee colony algorithm and kmeans(EABCk). In EABCk, the original artificial bee colony algorithm(called ABC) is enhanced by a new mutation operation and guided by the global best solution(called EABC). Then, the best solution is updated by kmeans in each iteration for data clustering. In the experiments, a set of benchmark functions was used to evaluate the performance of EABC with other comparative ABC variants. To evaluate the performance of EABCk on data clustering, eleven benchmark datasets were utilized. The experimental results show that EABC and EABCk outperform other comparative ABC variants and data clustering algorithms, respectively.

关键词： Data clustering k-means Artificial bee colony Mutation operation

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Indoor localization via l^1-graph regularized semi-supervised manifold learning

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 39-44,91页

作者： ZHU Yu-jia deng Zhong-liang JI Hao School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing 100876 China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

In this paper, a new -graph regularized semi-supervised manifold learning （LRSML） method is proposed for indoor localization. Due to noise corruption and non-linearity of received signal strength （RSS）, traditional approaches always fail to deliver accurate positioning results. The -graph is constructed by sparse representation of each sample with respect to remaining samples. Noise factor is considered in the construction process of -graph, leading to more robustness compared to traditional k-nearest-neighbor graph （kNN-graph）. The kNN-graph construction is supervised, while the -graph is assumed to be unsupervised without harnessing any data label information and uncovers the underlying sparse relationship of each data. Combining kNN-graph and -graph, both labeled and unlabeled information are utilized, so the LRSML method has the potential to convey more discriminative information compared to conventional methods. To overcome the non-linearity of RSS, kernel-based manifold learning method （k-LRSML） is employed through mapping the original signal data to a higher dimension Hilbert space. The efficiency and superiority of LRSML over current state of art methods are verified with extensive experiments on real data.

关键词： -graph indoor positioning semi-supervised manifold learning wireless local area network (WLAN)

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Experimental Study on the Penetration of Diesel and Biodiesel Spray Liquid Emerging from an Equilateral Triangular Orifice under Evaporative Conditions

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Journal of Thermal Science 2022年第5期31卷 1565-1574页

作者： YIN Bifeng YE Ze JIA Hekun YU Shenghao deng Weixin School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China Science and Technology on Scramjet Laboratory Hypervelocity Aerodynamics Institute of CARDMianyang621000China

This paper reports the results of an experimental study on the liquid phase characteristics of the biodiesel and diesel discharged from an equilateral triangular orifice and a circular orifice under different injection conditions by Mie-scattering *** results revealed that the biodiesel liquid penetration length was longer than that of diesel under the same injection *** addition,the increase of the chamber pressure was expected to enhance the interaction between air and fuel,resulting in the acceleration of the liquid phase breakup ***,with increasing chamber temperature,the liquid penetration of biodiesel was reduced less than that of *** was due to the high surface tension and viscosity of biodiesel which inhibited the chamber air entrainment and suppressed the liquid breakup ***,the higher probability of shorter diesel liquid penetration length indicated better air-fuel mixing than that of ***,the triangular orifice liquid length was shorter than that of the circular *** the stabilized liquid cone angle from the circular orifice was larger than that from the triangular orifice,indicating that using an equilateral triangular orifice has the potential to improve the air-fuel mixing process.

关键词： equilateral triangular orifice liquid penetration length biodiesel diesel

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Enhance hydrates formation with stainless steel fiber for high capacity methane storage

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Chinese Journal of Chemical Engineering 2022年第10期50卷 435-443页

作者： Zhixia deng Shuanshi Fan Yanhong Wang Xuemei Lang Gang Li School of Chemistry and Chemical Engineering South China University of TechnologyGuangzhou 510640China Guangdong Engineering Technology Research Center of Advanced Insulating Coating Zhuhai 519175China Institute of Modern Industrial Innovation South China University of TechnologyZhuhai 519175China key Laboratory of Fuel Cell Technology of Guangdong Province Guangzhou 510640China

In order to realize efficient gas storage of hydrate,stainless steel fiber(SSF)was added to 0.03%(mass)sodium dodecyl sulfate(SDS)solution for gas storage *** can not only improve the problem that hydration heat cannot be removed effectively in the hydration process,but also improve gas storage speed and gas storage by increasing hydrate nucleation *** the experimental conditions(273.2 k,5-9 MPa),the peaks of temperature rise in SDS+SSF systems were found to become much smaller than those in SDS *** maximum gas storage rate and the maximum methane uptake of SSF+SDS system reached 9.89-24.90 cm^(3)·g^(-1)·min^(-1) and 178.65-200.89 cm^(3)·(g H_(2)O)-1,*** with the surfactant SDS solution without SSF,they increased by 10.47%-33.22%and 9.16%-25.36%,*** effect of SSF length on gas storage performance was *** to the continuous thermal conduction network,longer SSF showed a higher gas storage capacity and methane uptake rate compared with shorter *** the same time,compared with other metal fillers,SSF+SDS not only had excellent gas storage performance,but also the amount of SSF(0.1 g·ml^(-1))was only 7.6%of foamed aluminum,and the volume gas storage density was increased by 145.4%.The use of stainless steel fiber made the best use of the thermal conductivity of metal,reduced the amount of metal used,and improved the volume density and mass density of gas storage.

关键词： Methane Stainless steelfiber Gas storagecapacity Hydrate Gas storagerate Heat transfer

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Hydrodynamic characteristics of a rectangular gas-driven inverse liquid-solid fluidized bed

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Particuology 2023年第7期78卷 86-96页

作者： Yicheng deng keying Ma jaqi Huang Yuanyuan Shao Jesse Zhu School of Chemical Engineering and Technology Tianjin UniversityTianjin300072China Department of Chemical and Biochemical Engineering Western UniversityLondonOntarioN6A3K7Canada Institute of Shaoxing Tianjin UniversityZhejiang312300China Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute The University of Nottingham Ningbo ChinaNingboZhejiang.315100China

The hydrodynamic characteristics of a rectangular gas-driven inverse liquid-solid fluidized bed(GDFB)using particles of different diameters and densities were investigated in *** gas bubbles cause a liquid upflow in the riser portion,enabling a liquid downflow that causes an inverse fluidization in the downer *** flow regimes(fixed bed regime,initial fluidization regime,complete fluidization regime,and circulating fluidization regime)and three transition gas velocities(initial fluidization gas velocity,minimum fluidization gas velocity,and circulating fluidization gas velocity)were identified via visual observation and by monitoring the variations in the pressure *** axial local bed voidage(e)of the downer first decreases and then increases with the increase of the gas *** the liquid circulation velocity and the average particle velocity inside the downer increase with the increase of the gas velocity in the riser,but decrease with the particle *** empirical formula was proposed to successfully predict the Richardson-Zaki index“n”,and the predicted e obtained from this formula has a±5%relative error when compared with the experimental e.

关键词： Gas-driven Inverse fluidized bed Flow regime Average particle velocity Liquid circulation velocity Bed voidage

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