Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction be...Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases： CO2 （φ=3%）＋H2O （φ=3%）＋N2 （φ= 94%） at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x= 0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773--1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10 ^-9 molos-locm 2 with direct current of 0.80 mA at 773 K.展开更多
Cassava is a staple food, feed and bioenergy crop important to the world especially in the tropics.Domesticated cassava is characterized by powerful carbohydrate accumulation but its wild progenitor is not.Here, we in...Cassava is a staple food, feed and bioenergy crop important to the world especially in the tropics.Domesticated cassava is characterized by powerful carbohydrate accumulation but its wild progenitor is not.Here, we investigated the transcriptional differences of eight c DNA libraries derived from developing leaf, stem and storage root of cassava cv. Arg7 and an ancestor line,W14, using next generation sequencing system. A total of41302 assembled transcripts were obtained and from these,25961 transcripts with FPKM≥3 in at least one library were named the expressed genes. A total of 2117, 1963 and3584 transcripts were found to be differentially expressed in leaf, stem and storage root(150 d after planting),respectively, between Arg7 and W14 and ascribed to 103,93 and 119 important pathways in leaf, stem and storage root, respectively. The highlight of this work is that the genes involved in light response, such as those for photosystem I(PSA) and photosystem II(PSB), other genes involved in light harvesting, and some of the genes in the Calvin cycle of carbon fixation were specially upregulated in leaf. Genes for transport and also for key rate-limiting enzymes(PFK, PGK and PK, GAPDH)coupling ATP consumption in glycolysis pathway were predominantly expressed in stem, and genes for sucrose degradation(INVs), amylose synthesis(GBSS) and hydrolysis(RCP1, AMYs), the three key steps of starch metabolism, and transport associated with energy translocation(ABC, AVPs and ATPase) and their upstream transcription factors had enhanced expression in storage root in domesticated cassava. Co-expression networks among the pathways in each organs revealed therelationship of the genes involved, and uncovered some of the important hub genes and transcription factors targeting genes for photosynthesis, transportation and starch biosynthesis.展开更多
We report here the structural, surface morphology, mechanical, and current voltage characteristics of Zn1-xMxO ceramic samples with various x and M （0.00≤〈 x ≤ 0.20, M = Ni, Cu）. It is found that the considered d...We report here the structural, surface morphology, mechanical, and current voltage characteristics of Zn1-xMxO ceramic samples with various x and M （0.00≤〈 x ≤ 0.20, M = Ni, Cu）. It is found that the considered dopants do not influence the well-known peaks related to the wurtzite structure of ZnO ceramics, while the shapes and the sizes of grains are clearly affected. The average crystalline diameters deduced from the SEM micrographs are between 2.06 μm and 4.8 μm for all samples. The oxygen element ratio is increased by both dopants. Interestingly, the potential barrier can be formed by adding Cu up to 0.20, while it is completely deformed by 0.025 Ni addition. The breakdown field can be enhanced up to 4138 V/cm by 0.025 Cu addition, followed by a decrease with further increase of Cu up to 0.20. On the other hand, a gradual decrease in Vickers microhardness is reported for both dopants, and the values in the Ni samples are higher compared to those in the Cu samples. The electricul conductivity is generally improved by Ni, while the addition of Cu improves it only in the over doped region （≥ 0.10）. These results are discussed in terms of the differences of valency and ferromagnetic ordering.展开更多
Nanostructured topological insulator materials such as ultrathin films, nanoplates, nanowires, and nanoribbons are attracting much attention for fundamental research as well as potential applications in low-energy dis...Nanostructured topological insulator materials such as ultrathin films, nanoplates, nanowires, and nanoribbons are attracting much attention for fundamental research as well as potential applications in low-energy dissipation electronics, spintronics, thermoelectrics, magnetoelectrics, and quantum computing due to their extremely large surface-to-volume ratios and exotic metallic edge/surface states. Layered Bi2Se3 and Bi2Te3 serve as reference topological insulator materials with a large nontrivial bulk gap up to 0.3 eV （equivalent to 3600 K） and simple single-Dirac-cone surface states. In this mini-review, we present an overview of recent advances in nanostructured topological in- sulator Bi2Se3 and Bi3Te3 from the viewpoints of controlled synthesis and physical properties. We summarize our recent achievements in the vapor-phase synthesis and structural characteriza- tion of nanostructured topological insulator Bi2Se3 and Bi2Te3, such as nanoribbons and ultrathin nanoplates. We also demonstrate the evolution of Raman spectra with the number of few-layer topo- logical insulators, as well as the transport measurements that have succeeded in accessing the surface conductance and surface state manipulations in the device of topological insulator nanostructures.展开更多
Main observation and conclusion Recently,the asymmetric nonfullerene acceptors(NFAs)with acceptor-donor-acceptor(A-D-A)structure have been developed rapidly,especially for the modification of asymmetric core,asymmetri...Main observation and conclusion Recently,the asymmetric nonfullerene acceptors(NFAs)with acceptor-donor-acceptor(A-D-A)structure have been developed rapidly,especially for the modification of asymmetric core,asymmetric side chains and asymmetric end groups.In this work,a novel asymmetric A-D-π-A type NFA with a noncovalently fused-ring core named PIST-4F is synthesized,containing an indacenodithieno[3,2-b]dithiophene(IDT),two strong electron-withdrawing end groups and an alkylthio-substituted thiopheneπ-bridge.Benefiting from the S···S noncovalent interaction between the sulfur atom onπ-bridge and the adjacent thiophene in IDT,the PIST-4F presents nearly planar geometry and extended conjugated area,resulting in the optimized electronic properties,charge transport,and film morphology compared to the symmetric NFA PI-4F.As a result,PM6:PIST-4F-based devices achieve a higher power conversion efficiency(PCE)of 13.8%,while the PM6:PI-4F-based devices only show a PCE of 7.1%.Notably,the PM6:PIST-4F-based devices processed with nonhalogen solvent toluene exhibit an excellent PCE as high as 13.1%.These results indicate that PIST-4F is an effective acceptor for high-efficiency organic solar cells.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20771079）.
文摘Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α （x=0.10, 0.15, 0.20, 0.30） were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases： CO2 （φ=3%）＋H2O （φ=3%）＋N2 （φ= 94%） at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x= 0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773--1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10 ^-9 molos-locm 2 with direct current of 0.80 mA at 773 K.
基金supported by the National Natural Science Foundation of China (31261140363, 31171230)the National Basic Research and Development Program (2010CB126601)+1 种基金China Agriculture Research System (CARS-12wwq)the Hainan Province Innovative Research Team Foundation (2016CXTD013)
文摘Cassava is a staple food, feed and bioenergy crop important to the world especially in the tropics.Domesticated cassava is characterized by powerful carbohydrate accumulation but its wild progenitor is not.Here, we investigated the transcriptional differences of eight c DNA libraries derived from developing leaf, stem and storage root of cassava cv. Arg7 and an ancestor line,W14, using next generation sequencing system. A total of41302 assembled transcripts were obtained and from these,25961 transcripts with FPKM≥3 in at least one library were named the expressed genes. A total of 2117, 1963 and3584 transcripts were found to be differentially expressed in leaf, stem and storage root(150 d after planting),respectively, between Arg7 and W14 and ascribed to 103,93 and 119 important pathways in leaf, stem and storage root, respectively. The highlight of this work is that the genes involved in light response, such as those for photosystem I(PSA) and photosystem II(PSB), other genes involved in light harvesting, and some of the genes in the Calvin cycle of carbon fixation were specially upregulated in leaf. Genes for transport and also for key rate-limiting enzymes(PFK, PGK and PK, GAPDH)coupling ATP consumption in glycolysis pathway were predominantly expressed in stem, and genes for sucrose degradation(INVs), amylose synthesis(GBSS) and hydrolysis(RCP1, AMYs), the three key steps of starch metabolism, and transport associated with energy translocation(ABC, AVPs and ATPase) and their upstream transcription factors had enhanced expression in storage root in domesticated cassava. Co-expression networks among the pathways in each organs revealed therelationship of the genes involved, and uncovered some of the important hub genes and transcription factors targeting genes for photosynthesis, transportation and starch biosynthesis.
文摘We report here the structural, surface morphology, mechanical, and current voltage characteristics of Zn1-xMxO ceramic samples with various x and M （0.00≤〈 x ≤ 0.20, M = Ni, Cu）. It is found that the considered dopants do not influence the well-known peaks related to the wurtzite structure of ZnO ceramics, while the shapes and the sizes of grains are clearly affected. The average crystalline diameters deduced from the SEM micrographs are between 2.06 μm and 4.8 μm for all samples. The oxygen element ratio is increased by both dopants. Interestingly, the potential barrier can be formed by adding Cu up to 0.20, while it is completely deformed by 0.025 Ni addition. The breakdown field can be enhanced up to 4138 V/cm by 0.025 Cu addition, followed by a decrease with further increase of Cu up to 0.20. On the other hand, a gradual decrease in Vickers microhardness is reported for both dopants, and the values in the Ni samples are higher compared to those in the Cu samples. The electricul conductivity is generally improved by Ni, while the addition of Cu improves it only in the over doped region （≥ 0.10）. These results are discussed in terms of the differences of valency and ferromagnetic ordering.
文摘Nanostructured topological insulator materials such as ultrathin films, nanoplates, nanowires, and nanoribbons are attracting much attention for fundamental research as well as potential applications in low-energy dissipation electronics, spintronics, thermoelectrics, magnetoelectrics, and quantum computing due to their extremely large surface-to-volume ratios and exotic metallic edge/surface states. Layered Bi2Se3 and Bi2Te3 serve as reference topological insulator materials with a large nontrivial bulk gap up to 0.3 eV （equivalent to 3600 K） and simple single-Dirac-cone surface states. In this mini-review, we present an overview of recent advances in nanostructured topological in- sulator Bi2Se3 and Bi3Te3 from the viewpoints of controlled synthesis and physical properties. We summarize our recent achievements in the vapor-phase synthesis and structural characteriza- tion of nanostructured topological insulator Bi2Se3 and Bi2Te3, such as nanoribbons and ultrathin nanoplates. We also demonstrate the evolution of Raman spectra with the number of few-layer topo- logical insulators, as well as the transport measurements that have succeeded in accessing the surface conductance and surface state manipulations in the device of topological insulator nanostructures.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.51773142 and 51973146)the Jiangsu Provincial Natural Science Foundation(Grant No.BK20190099)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science&Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Main observation and conclusion Recently,the asymmetric nonfullerene acceptors(NFAs)with acceptor-donor-acceptor(A-D-A)structure have been developed rapidly,especially for the modification of asymmetric core,asymmetric side chains and asymmetric end groups.In this work,a novel asymmetric A-D-π-A type NFA with a noncovalently fused-ring core named PIST-4F is synthesized,containing an indacenodithieno[3,2-b]dithiophene(IDT),two strong electron-withdrawing end groups and an alkylthio-substituted thiopheneπ-bridge.Benefiting from the S···S noncovalent interaction between the sulfur atom onπ-bridge and the adjacent thiophene in IDT,the PIST-4F presents nearly planar geometry and extended conjugated area,resulting in the optimized electronic properties,charge transport,and film morphology compared to the symmetric NFA PI-4F.As a result,PM6:PIST-4F-based devices achieve a higher power conversion efficiency(PCE)of 13.8%,while the PM6:PI-4F-based devices only show a PCE of 7.1%.Notably,the PM6:PIST-4F-based devices processed with nonhalogen solvent toluene exhibit an excellent PCE as high as 13.1%.These results indicate that PIST-4F is an effective acceptor for high-efficiency organic solar cells.
