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Science China Chemistry 2016年第8期59卷 948-958页

作者： Suna Wang Ranran Ma Zhiwei Chen Yunwu Li Tingting Cao Changhui Zhou Junfeng Bai Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology School of Chemistry and Chemical EngineeringLiaocheng UniversityLiaocheng 252059China State Key Laboratory of coordination Chemistry School of Chemistry and Chemical EngineeringNanjing National Laboratory of MicrostructuresNanjing UniversityNanjing 210093China

Two types of lanthanide coordination polymers, namely, [Ln（PA）（NO3）（DMA）3]n （Ln=Gd （1）, Dy （2）, Eu （3）, Tb （4））（type I）, and {[Ln2（PA）3（DMF）4]＇2DMF} （Ln=Eu （5）, Tb （6））（type II）（PA=Pamoic acid, DMA=dimethylacetamide, DMF=N,N-dimethylformamide）, have been synthesized by the reaction of Ln（NO3）a-6H20 with pamoic acid through layer diffusion method. These complexes were characterized by single crystal X-ray diffraction, infrared spectroscopy （IR）, thermogravimetric analysis （TGA）, fluorescence and magnetic measurements. Solvents and lanthanide atoms in the reaction play an important role in controlling different structures. Type I demonstrated 1-D linear chain structure connected by Ln atoms and PA ligands. Type II exhibited non-interpenetrating 3-D 6-connected 43612 nets based on binuclear [Ln2（CO2）6（DMF）4] cores. Magnetic properties of complexes 1-4 were investigated in details. Complex 1 shows significant magnetocaloric effect with -△Sm=20.37 J kg^-1 K^-1 at 3.0 K and 7 T. Complex 2 exhibits slow relaxation of the magnetization. Complexes 3-6 exhibit both ligand- and metal-centered fluorescent properties. Complex 6 demonstrates fluorescent sensing of DMF and Cu^2＋ ion.

关键词： lanthanide-organic frameworks solvent-directed magnetization relaxation magnetocaloric effect fluorescence sensing

QoS Support Polling Scheme for Multimedia Traffic in Wireless LAN MAC Protocol

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Tsinghua Science and Technology 2008年第6期13卷 754-758页

作者：杨志军赵东风 Department of Communication Engineering Yunnan University Information Center of Educational and scientific Institute Educational Department of Yunnan Province

Quality of service （QoS） support is a key attribute for multimedia traffic including video, voice, and data in wireless local area networks （LANs） but is limited in 802.11-based wireless LANs. A polling-based scheme called the point coordination function （PCF） was developed for 802.11 LANs to support the transmission of multimedia traffic. However, the PCF is not able to meet the desired practical traffic differentiation requirements for real-time data. This paper describes a QoS support polling scheme based on the IEEE 802.11 medium access control （MAC） protocol. The scheme uses a two-level polling mechanism with the QoS classes differentiated by two different access policies. Stations with higher priority traffic such as key or real-time data form the first level and can access the common channel through an exhaustive access policy. Other stations with lower priority traffic form the second level and can access the channel through a gated access policy. A system model based on imbedded Markov chain theory and a generation function were setup to explicitly analyze the mean information packet waiting time of the two-level polling scheme. Theoretical and simulation results show that the new scheme efficiently differentiates services to guarantee better QoS and system stability.

关键词： polling system exhaustive access policy gated access policy information packet waiting time quality of service (QoS)

Cation-induced assembly of Zn(Ⅱ),Cd(Ⅱ) and Hg(Ⅱ) coordination complexes and DFT calculations to evaluate weak interactions between the helical chains

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Science China Chemistry 2011年第1期54卷 173-179页

作者： GENG WenQian LI XianLei YIN JianHui KE WeiZai HAO FuYin XU GuoYi ZHOU HongPing WU JieYing TIAN YuPeng Department of Chemistry Anhui University Hefei 230039 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China State Key Laboratory of coordination Chemistry Nanjing University Nanjing 210093 China

Two new coordination polymers [ZnLI2]∞ （1） and [CdLI2]∞ （2）（L： 3,6-di-（1,2,4-triazole-l-yl）-N-hexylcarbazole） were syn- thesized and their crystal structures were determined by single-crystal X-ray diffraction techniques. Complexes are both constructed with the helical chains along the 2l screw axis. The coordination bond, C-H...I weak interactions and π-π interactions play significant roles in constructing their 3D or 2D frameworks. Two different DFT calculations are performed for the weak interactions between the helical chains of the three different coordination polymers （[ZnLI2]∞[CdLI2]∞, and the reported [HgLI2]∞）. The results reveal that weak interactions play important roles in these supramolecular systems of helical configuration, namely, the trend is the shorter H…I distance and π-π stacking distance, the stronger the intermolecular interactions. The photoluminescence of the complexes measured in the solid state at room temperature indicates that the emission intensity varies extensively, which can be rationalized by the heavy atom effect. helical configuration, weak interactions, DFT calculations, photoluminescence

关键词： helical configuration weak interactions DFT calculations photoluminescence

An Assessment of Women Participation in Community-Based Natural Resource Conservation in Southeast Zimbabwe

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Open Journal of Ecology 2020年第4期10卷 189-199页

作者： Clayton Mashapa Patience Zisadza-Gandiwa Elias Libombo Patience Mhuriro-Mashapa Never Muboko Edson Gandiwa School of Wildlife Ecology and Conservation Chinhoyi University of Technology Chinhoyi Zimbabwe International coordination Office for Greater Mapungubwe Transfrontier Conservation Area Causeway Zimbabwe scientific Services Gonarezhou National Park Chiredzi Zimbabwe Department of Agricultural Economics University of Zimbabwe Harare Zimbabwe

The study assessed women’s participation in the Communal Area Management Programme for Indigenous Resources (CAMPFIRE) activities in southeast Zimbabwe. The study collected data using an interview questionnaire administered to five CAMPFIRE committees in October 2014. There were relatively no differences in the selected attributes on CAMPFIRE committee composition across the five study communities i.e., 1) the number of people and their level of education, and 2) gender and age composition. There were more men (5 ± 0.11) than women (2 ± 0.02) in CAMPFIRE program committees across the five study communities. Men dominate leadership and decision making over CAMPFIRE in south-eastern Zimbabwe. Yet, it is the women who use most of the natural resources at household level, such as game meat, wild fruits and wild vegetables as relish, fuel wood as source of energy for cooking, and baskets woven from woodland products. It was concluded that despite all the benefits that a gender sensitive approach could bring to CAMPFIRE, women participation in CAMPFIRE programs in southeast Zimbabwe was still low as evidenced by their numbers in committees that make decisions for the program. There was need for deliberate action to ensure increased women participation in CAMPFIRE programs, especially at the decision-making level. A certain number of committee positions in CAMPFIRE should be reserved for women.

关键词： CAMPFIRE Empowerment Gender Natural Resource Women Southern Africa

A Continuous Authentication Protocol Without Trust Authority for Zero Trust Architecture

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China Communications 2022年第8期19卷 198-213页

作者： Lei Meng Daochao Huang Jiahang An Xianwei Zhou Fuhong Lin School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China National Computer Network Emergency Response Technical Team/coordination Center of China(CNCERT/CC) Beijing 100029China Shunde Graduate School of University of Science and Technology Beijing Guangdong528399China

Zero-trust security is a novel concept to cope with intricate access,which can not be handled by the conventional perimeter-based architecture *** device-to-device continuous authentication protocol is one of the most crucial cornerstones,especially in the IoT *** the zero-trust architecture,trust does not rely on any position,person or ***,to the best of our knowledge,almost all existing device-to-device continuous authentication relies on a trust authority or a node to generate secret keys or secret *** is betrayed by the principle of zero-trust *** this paper,we employ the blockchain to eliminate the trusted *** node is chosen to produce the public parameter and secret keys for two entities through the practical Byzantine fault tolerance consensus ***,the devices are categorized into three folds:trusted device,suspected device and untrusted *** the first two can participate in authentication,and they have different lengths of security parameters and intervals to reach a better balance between security and *** we prove the security of the initial authentication part in the eCK model and give an informal analysis of the continuous authentication ***,we implement the proposed protocol on simulated *** result illustrates that our scheme is highly efficient,and the continuous authentication only costs around 0.1ms.

关键词： continuous authentication zero-trust architecture device-to-device blockchain IoT

SSD Real-Time Illegal Parking Detection Based on Contextual Information Transmission

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Computers, Materials & Continua 2020年第1期62卷 293-307页

作者： Huanrong Tang Aoming Peng Dongming Zhang Tianming Liu Jianquan Ouyang Key Laboratory of Intelligent Computing and Information Processing Ministry of EducationCollege of Information EngineeringXiangtan UniversityXiangtan411105China National Computer Network Emergency Response Technical Team/coordination Center of China Beijing100029China Department of Computer Science the University of GeorgiaAthensGeorgiaUSA

With the improvement of the national economic level,the number of vehicles is still increasing year by *** to the statistics of National Bureau of Statics,the number is approximately up to 327 million in China by the end of 2018,which makes urban traffic pressure continues to rise so that the negative impact of urban traffic order is *** parking-the common problem in the field of transportation security is urgent to be solved and traditional methods to address it are mainly based on ground loop and manual supervision,which may miss detection and cost much *** to the rapidly developing deep learning sweeping the world in recent years,object detection methods relying on background segmentation cannot meet the requirements of complex and various scenes on speed and ***,an improved Single Shot MultiBox Detector(SSD)based on deep learning is proposed in our study,we introduce attention mechanism by spatial transformer module which gives neural networks the ability to actively spatially transform feature maps and add contextual information transmission in specified ***,we found out the best connection layer in the detection model by repeated experiments especially for small objects and increased the precision by 1.5%than the baseline SSD without extra training ***,we designed an illegal parking vehicle detection method by the improved SSD,reaching a high precision up to 97.3%and achieving a speed of 40FPS,superior to most of vehicle detection methods,will make contributions to relieving the negative impact of illegal parking.

关键词： Contextual information transmission illegal parking detection spatial attention mechanism deep learning

Metal-free cascade boron-heteroatom addition and alkylation with diazo compounds

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Chinese Chemical Letters 2021年第2期32卷 691-694页

作者： Jiahang Lv Binlin Zhao Ying Han Yu Yuan Zhuangzhi Shi College of Chemistry and Chemical Engineering.Yangzhou University Yangzhou 225002China State Key Laboratory of coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210093China Department of Chemistry and Materials Science College of ScienceNanjing Forestry UniversityNanjing 210037China

Transition metal-catalyzed carbene transfer reaction is one of the most notable advances for C-C bond formation reactionsduring the past decade,which has been widely employed in the preparation of C3-substituted indoles,Here,we described an efficient exa mple of catalyst-and metal-free aminobo ration of alkynes and C—C bond formation with diazo compounds to produce C3-substituted indoles,Diverse alkynyla nilines and diazo compounds ca n be utilized for this tandem transfo rmation under mild reaction conditions,re sulting in broad functional group co ***,this metal-free strategy can be extended to construct substituted benzofurans.

关键词： Indoles Aminoboration Metal-free BCl3 Diazo compounds

Analysis and design of resistance-wire heater in MOCVD reactor

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Journal of Central South University 2014年第9期21卷 3518-3524页

作者：曲毓萱王斌胡仕刚吴笑峰李志明唐志军李劲胡莹璐 Advanced Technology Generalization Institute of CNGC The Center of coordination and Support of State Administration of Science Technology and Industry for National Defence School of Information and Electrical Engineering Hunan University of Science and Technology School of Information Science and Engineering University of Jinan The 41st Institute of China Electronics Technology Group Corporation

Metal organic chemical vapor deposition(MOCVD) is a key equipment in the manufacturing of semiconductor optoelectronic devices and microwave devices in industry. Heating system is a vital part of MOCVD. Specific heating device and thermal control technology are needed for each new reactor design. By using resistance-wire heating MOCVD reaction chamber model, thermal analysis and structure optimization of the reactor were developed from the vertical position and the distance between coils of the resistance-wire heater. It is indicated that, within a certain range, the average temperature of the graphite susceptor varies linearly with the vertical distance of heater to susceptor, and with the changed distances between the coils; furthermore, single resistance-wire heater should be placed loosely in the internal and tightly in the external. The modulate accuracy of the temperature field approximately equals the change of the average temperature corresponding to the change of the coil position.

关键词： metal organic chemical vapor deposition (MOCVD) reactor design thermal analysis filament heating

Cd3(C3N3S3)2 coordination polymer/graphene nanoarchitectures for enhanced photocatalytic H2O2 production under visible light

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Science Bulletin 2017年第9期62卷 610-618页

作者： Jie Xu Zhenye Chen Hongwen Zhang Guibin Lin Huaxiang Lin Xuxu Wang Jinlin Long State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350116China The Institute of scientific and Industrial Research(SANKEN) Osaka UniversityOsaka 567-0047Japan

For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight" and given impetus to the universal's efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide(H_2O_2) is undoubtedly a good choice,which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd_3(C_3N_3S_3)_2, was found to be a robust photocatalyst for H_2O_2 generation under visible light irradiation. To further improve the H_2O_2 generation efficiency, adhering the octahedron to reduced graphene(rGO) was applied as the strategy herein. The study shows that by adhering Cd_3(C_3N_3S_3)_2to rGO, the formation of H_2O_2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd_3(C_3N_3S_3)_2polymer to rGO for the improvement of the polymer's photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.

关键词： Photocatalysis coordination polymer rGO Cd3(C3N3S3)2 H2O2 generation

Non-FCC rich Au crystallites exhibiting unusual catalytic activity

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Nano Research 2017年第7期10卷 2271-2279页

作者： Gangaiah Mettela Nisha Mammen Joydip Joardar Shobhana Narasimhan Giridhar U. Kulkarni Thematic Unit of Excellence on Nanochemistry and Chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur Bangalore 560 064 India Theoretical Sciences Unit Jawaharlal Nehru Centre forAdvanced Scientific Research Jakkur Bangalore 560 064 India IntemationalAdvanced Research Centre for Powder Metallurgy & New Materials Balapur Hyderabad 500 005 India Centre for Nano and Soft Matter Sciences Jalahalli Bangalore 560 013 India

Bipyramidal Au microcrystallites have been synthesized by thermalizing a Au-organic complex in the presence of Ag（I） ions, the latter acting as a shape- directing agent. With a highly corrugated morphology leading to strain-induced non-face-centered cubic （non-FCC） Au phases, the non-FCC portion can be tuned by varying the Ag/Au ratio, as verified by diffraction measurements. For a Ag/Au ratio of 0.34, the non-FCC Au portion was as high as 85%. X-ray microdiffraction and electron diffraction measurements reveal that the non-FCC contribution comes primarily from bipyramids, while other microcrystallites, namely, tetrahexahedrons and hexagrams, host non-FCC phases only at the edges and, to an even lesser extent, at the comers. When used as a catalyst for p-nitrophenol reduction, the non-FCC microcrystallites exhibit a significantly enhanced activity compared to FCC Au, which shows only negligible activity. These results are in accordance with trends in the values of two descriptors of reactivity calculated from first principles： The effective coordination number is found to decrease and the d-band center is found to increase in energy going from the FCC to the non-FCC phases of Au. Our findings contradict the general notion that Au is catalytically active only in nanodimensions and is otherwise inert; in this system, its activity arises from the non-FCC phases.

关键词： Au microcrystallites non-face-centered cubic(non-FCC) phases microbeam X-raydiffraction (XRD) catalysis effective coordinationnumber