The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape....The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape. In the design of target plant community and configuration plants,it is required to select as far as possible plants that can blossom and bear fruit or pods. Then seeds of these plants can be harvested,processed and sold,and applied for other projects,so as to develop into a complete forest and grass seed industry chain. This not only reasonably utilizes land resources,but also provides a new approach to the problem of insufficient fine forest seed sources in China. This paper discussed the use of land resources in road side slope and forest and grass seed selection and breeding technology,and elaborated the industrialized development paths for forest and grass seed industries in road side slope. Finally,it arrived at following recommendations.( i) The construction of forest and grass industry economic belt using land resources in road side slope can realize maximum land value. Building a road can help people there get rich,and the type of land and water cultivates its type of forest and grass.( ii) It can make up for the losses incurred from construction of expressway and high-speed rail or destroying forest land,and it can increase farmers' income.( iii) It can increase the supply of domestic seeds,reduce seed import,save foreign exchange,and partly solve the problem of insufficient supply of forest and grass seeds.( iv) It is able to form a complete forest and grass seed industry economic cycle chain,increase employment,and provide new approaches for enriching and benefiting farmers.展开更多
To the Editor:To control the coronavirus disease 2019(COVID-19)pandemic and reduce the complications and deaths resulting from the transmission of the disease,a variety of COVID-19 vaccines,such as mRNA vaccines,adeno...To the Editor:To control the coronavirus disease 2019(COVID-19)pandemic and reduce the complications and deaths resulting from the transmission of the disease,a variety of COVID-19 vaccines,such as mRNA vaccines,adenovirus-vector vaccines,inactivated viral vaccines,and others,have been licensed for emergency use.Most of these vaccines were rolled out in different countries following the successful completion of phase 3 clinical trials.Scale-up of vaccine production and vaccination have provided notable protection to large populations,although some vaccines may cause side effects.Furthermore,as the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has mutated and spread further over time,some notable novel variants have emerged,but whether these variants are vulnerable to currently available vaccines is yet to be determined.展开更多
The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quant...The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.展开更多
基金Supported by National Spark Plan Project(2010GA781004)Science and Technology Planning Project of Shenzhen(GCZX2015051514435234,CXZZ20150527171538718,and CXZZ20140422142833835)
文摘The construction of expressway and high-speed rail is at the sacrifice of the soil ecological environment. It brings about much damaged land and bare slope. It is necessary to restore vegetation and rebuild landscape. In the design of target plant community and configuration plants,it is required to select as far as possible plants that can blossom and bear fruit or pods. Then seeds of these plants can be harvested,processed and sold,and applied for other projects,so as to develop into a complete forest and grass seed industry chain. This not only reasonably utilizes land resources,but also provides a new approach to the problem of insufficient fine forest seed sources in China. This paper discussed the use of land resources in road side slope and forest and grass seed selection and breeding technology,and elaborated the industrialized development paths for forest and grass seed industries in road side slope. Finally,it arrived at following recommendations.( i) The construction of forest and grass industry economic belt using land resources in road side slope can realize maximum land value. Building a road can help people there get rich,and the type of land and water cultivates its type of forest and grass.( ii) It can make up for the losses incurred from construction of expressway and high-speed rail or destroying forest land,and it can increase farmers' income.( iii) It can increase the supply of domestic seeds,reduce seed import,save foreign exchange,and partly solve the problem of insufficient supply of forest and grass seeds.( iv) It is able to form a complete forest and grass seed industry economic cycle chain,increase employment,and provide new approaches for enriching and benefiting farmers.
基金Logistic Support Department of Central Military Commission Health Care Project(No.21BJZ35)National Natural Science Foundation of Beijing(No.7212104)
文摘To the Editor:To control the coronavirus disease 2019(COVID-19)pandemic and reduce the complications and deaths resulting from the transmission of the disease,a variety of COVID-19 vaccines,such as mRNA vaccines,adenovirus-vector vaccines,inactivated viral vaccines,and others,have been licensed for emergency use.Most of these vaccines were rolled out in different countries following the successful completion of phase 3 clinical trials.Scale-up of vaccine production and vaccination have provided notable protection to large populations,although some vaccines may cause side effects.Furthermore,as the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has mutated and spread further over time,some notable novel variants have emerged,but whether these variants are vulnerable to currently available vaccines is yet to be determined.
基金supported financially by the National Natural Science Foundation of China (Nos. 51672139, 51472127 and 51272144)the Projects Supported by the Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education (No. KF2016-01)
文摘The rational assembly of quantum dots on two-dimensional(2 D) carbonaceous materials is very promising to produce materials, but remains a challenge. Here, we develop an assembly strategy of growing Na3 V2(PO4)3 quantum dots with superlattice structure(NVP-QDs-SL) for obtaining precise control of the size, distribution and crystallinity. The multifunctional lignocelluloses(LCs) used as a hard carbon source induce heterogeneous nucleation and confined growth of NVP-QDs-SL, leading to the uniform distribution of NVP-QDs-SL in H/S-doped hard carbon ultra-thin nanosheets(HCS). Detailed electrochemical analysis results from sodium-ion batteries of NVP-QDs-SL show that NVP-QDs-SL could trap the electrons inside HCS, significantly enhancing Na ion storage and transfer kinetics. Compared to the common Na3 V2(PO4)3 nanoparticle cathode, the NVP-QDs-SL/HCS cathode exhibits a high reversible capacity of 149.2 m A h g^-1 at a 0.1 C rate, which is far beyond the theoretical capacity of Na3 V2(PO4)3(117.6 m A h g^-1).At the ultrahigh current rate of 100 C, this cathode still remains a high discharge capacity of 40 m A h g-1.Even after cycling at 20 C over 3000 cycles, an ultrahigh coulombic efficiency close to 100% is still obtained,highlighting its excellent long cycling life, remarkable rate performance and energy density.
