Carboxylative Suzuki coupling reactions of benzyl chlorides with allyl pinacolborate catalyzed by palladium nanoparticles

Palladium-catalyzed carboxylative Suzuki coupling reactions of benzyl chlorides with allyl pinacol-borate were successfully conducted in the absence of any extra ligand to produce β,γ-unsaturated esters in satisfactory to good yields. The carboxylative Suzuki coupling reaction proceeded smooth-ly under mild conditions in the presence of palladium nanoparticles generated in situ through the formation of a π-benzylpalladium chloride intermediate.

Long-Term Preservation of Electronic Record Based on Digital Continuity in Smart Cities

Under the co-promotion of the wave of urbanization and the rise of data science,smart cities have become the new concept and new practice of urban development.Smart cities are the combination of information technology represented by the Internet of Things,cloud computing,mobile networks and big data,and urbanization.How to effectively achieve the long-term preservation of massive,heterogeneous,and multi-source digital electronic records in smart cities is a key issue thatmust be solved.Digital continuity can ensure the accessibility,integrity and availability of information.The quality management of electronic record,like the quality management of product,will run through every phase of the urban lifecycle.Based on data quality management,this paper constructs digital continuity of smart city electronic records.Furthermore,thework in this paper ensures the authenticity,integrity,availability and timeliness of electronic documents by quality management of electronic record.This paper elaborates on the overall technical architecture of electronic record,as well as the various technical means needed to protect its four characteristics.

Front-end Control Mechanism of Electronic Records

In the digital era,how to ensure the authenticity and integrity of elec-tronic records has become an open challenging issue.Front-end control is an important concept as well as a basic principle in electronic record management.Under the instruction of front-end control,many original management links in the record-management stage are required to move forward,and the managers enter the formation stage of the electronic records to ensure the originality.How-ever,the front-end control technique primarily focuses on transaction manage-ment,and it lacks the strategy of providing the control of electronic records.In this paper,a novel electronic record front-end control mechanism is proposed by adopting proxy re-encryption and requiring archivists to participate in the man-agement of electronic records before the record is created to solve the problem.Specifically,when an electronic record is generated,the proposed mechanism interacts with the producer of the electronic record to generate a corresponding encryption key.Moreover,electronic records are encrypted by the key to protect their confidentiality,which can prevent the leakage of electronic record informa-tion.In addition,when transferring the electronic record,archivists use proxy re-encryption technology to convert electronic records,allowing management by an archivist,ensuring their originality and authenticity.

消费地原则在B2B跨境转让服务或无形资产中的应用

经济全球化和经济数字化使各国的税收制度相互影响愈加深刻。加强跨境转让服务或无形资产的增值税征收管理,避免双重征税和非故意不征税成为各国政府面临的难题。OECD在《国际增值税/货物及服务税指南》中提出:在国际贸易中应当按照消费地原则征收增值税,以实现税收中性。本文借鉴OECD《国际增值税/货物及服务税指南》,以案例形式分析了在B2B跨境转让服务或无形资产时,如何应用消费地原则,判断单一位置实体(SLE)、多重位置实体(MLE)的税收管辖权,提出我国应当从坚持消费地原则征税、完善消费地原则判断标准、加强非居民企业增值税管理等方面健全相关增值税制度。

Reduction of Low-grade Manganese Dioxide Ore Pellets by Biomass Wheat Stalk

An investigation on reducing low-grade manganese dioxide ore pellets was carried out by using wheat stalk as reductant. The main impact factors of reduction percent such as particle size, biomass/ore ratio, heating rate, nitrogen flow rate, temperature and time in reduction process were discussed. The morphology and component of manganese dioxide ore particle at different stages were also analyzed by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. The results show the increase of the reduction temperature and time, biomass/ore ratio, and the decrease of particle size, heating rate and nitrogen flow rate can significantly enhance reduction efficiency. The reduction kinetic of the manganese ore is controlled by three-dimensional mass diffusion of gaseous reductive volatiles passing from the surface to the core of the ore particles. The activation energy E and frequency factor A were calculated to be 24.15 kJ.mol^-1 and 166 min^-1, respectively. Biomass pyrolysis volatiles adsorbed onto the surface of the ore particle leads to serious variation of the microstructures and chemical composition of the manganese ore particles.

Accelerated plasma degradation of organic pollutants in milliseconds and examinations by mass spectrometry

The rapid degradation of organic pollutants,process monitoring and online controlling to obtain advanced products and decreased by-products are great and challenging tasks in environmental treatments.Herein,an accelerated plasma degradation in milliseconds was achieved by combining electrospray-based acceleration and plasma-based degradation.Taking the degradation of chloroaniline as an example,97%of the degradation can be achieved in milliseconds.The velocity distribution of droplets was determined to be 40-50 m/s after being degraded for 0.30 ms,which exhibited different degradation behaviors in different milliseconds.Simultaneously,by virtue of the real-time and on-line detection ability of ambient mass spectrometry,intermediates,by-products and advanced products were monitored.Therefore,degradation mechanisms for different degradation times were proposed,which would provide theoretical guidance on obtaining efficient and green degradation.The fabrication,examining and understanding of accelerated plasma degradation not only enlarged application of accelerated reactions,but also promoted green and efficient degradation for environmental treatments.