Establishment of a highly efficient regeneration system for the mature embryo of wheat will provide a convenient tool for wheat tissue culture and transformation, thereby facilitating the transformation of foreign gen...Establishment of a highly efficient regeneration system for the mature embryo of wheat will provide a convenient tool for wheat tissue culture and transformation, thereby facilitating the transformation of foreign genes into wheat. By using the mature embryos derived from 20 different wheat lines including Shi 4185, Yumai 66, Lunxuan 987, CB037, Yangmai 6, Xinchun 9, Bobwhite, Han 6172, Zheng 9023, Jimai 20, Ningchun 4, and Jing 411, the effects of some factors including inoculation methods, initiating culture media, organic additives, antioxidants, and auxins on the regeneration from the explants were evaluated. The results indicated that the scraping embryo culture was better than the whole embryo culture, the Aa medium was better than the SD2 medium and dicamba was better than 2,4-D in increasing the regeneration frequency. An Adi medium was established in this study by adding silver nitrate, cysteine, ascorbic acid, dicamba, glutamine into the Aa medium at the concentration of 4,40, 100, 2, and 5 mg L^-1, respectively. By using the Adi medium and the scraping technique, the regeneration frequencies of the mature embryos of CB037, Lunxuan 987, Hart 6172, Yangmai 6, Bobwhite, Zheng 9023, Shi 4 185, and Jimai 20 became 85.6, 60,1, 46.0, 42.1,42.0, 34.0, 33.0, and 32.0%, respectively, which were about 5-8 times higher than that obtained from the conventional culture mediums and techniques. This novel regeneration system could be helpful in wheat transformation.展开更多
Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on...Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on the combination of beneficial alleles at the quantitative trait loci （QTLs）. However, the conventional cross breeding method is extremely time-consuming and laborious for pyramiding multiple QTLs. In certain cases, this approach might be technically difficult because of close linkage between genes separately responsible for desirable and undesirable traits.展开更多
Based on reserve abundance,large gas fields in China can be divided into two types：type one of high abundance large gas fields,dominated by structural gas reservoirs; type two of low abundance large gas fields,domina...Based on reserve abundance,large gas fields in China can be divided into two types：type one of high abundance large gas fields,dominated by structural gas reservoirs; type two of low abundance large gas fields,dominated by stratigraphic and lithologic gas reservoirs.The formation of these two types of large gas fields is related to the highly efficient accumulation of natural gas.The accumulation of high abundance gas fields is dependent on the rapid maturation of the source kitchen and huge residual pressure difference between the gas source kitchen and reservoir,which is the strong driving force for natural gas migration to traps.Whereas the accumulation of low abundance gas fields is more complicated,involving both volume flow charge during the burial stage and diffusion flow charge during the uplift stage,which results in large area accumulation and preservation of natural gas in low porosity and low permeability reservoirs.This conclusion should assist gas exploration in different geological settings.展开更多
A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium（Ill） complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device e...A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium（Ill） complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device exhibits a greenish-yellow emission with the peak at 523nm and a strong shoulder at 557nm, corresponding to Commission Internationale de l＇Eclairage coordinates of （0.38, 0.68）. The full width at half maximum of the device is 93 nm, which is broader than the fac-tris（2-phenylpyridine）iridium [Ir（ppy）3] based reference device of 78 nm. Meanwhile, a maximum current efficiency of 62.6 cd/A （47.51m/W） is obtained. This result is higher than a maximum current efficiency of 54.8 cd/A （431m/W） of the Ir（ppy）a based device. The results indicate that this new iridium complex may have potential applications in fabricating high color rendering index white organic light emitting diodes.展开更多
A novel SrSn(OH)_(6) photocatalyst with large plate and particle size were synthesized via a facile chemical precipitation method. The photocatalytic activity of the SrSn(OH)_(6) was evaluated by the removal of NO at ...A novel SrSn(OH)_(6) photocatalyst with large plate and particle size were synthesized via a facile chemical precipitation method. The photocatalytic activity of the SrSn(OH)_(6) was evaluated by the removal of NO at ppb level under UV light irradiation. Based on the ESR measurements, SrSn(OH)_(6) photocatalyst was found to have the ability to generate the main active species of O_(2)^(·-), ^(·)OH and ^(1)O_(2) during the photocatalytic process. Moreover, SrSn(OH)_(6) photocatalyst not only exhibits high photocatalytic activity for NO removal (79.6%), but also has good stability after five cycles. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to investigate the NO_(x) transfer pathway and the intermediate products distribution during the adsorption and photocatalytic NO oxidation process. The present work not only provides an efficient material for air pollutants purification at room temperature but also in-depth understanding of the mechanism involved in the photocatalytic NO removal process.展开更多
Since its first application to induce mutations in mammalian cells （Cong et al., 2013： Mall et al., 2013）, CRISPR/Cas9 has rapidly become a routine technique to perform genome editing in a variety of biological sys...Since its first application to induce mutations in mammalian cells （Cong et al., 2013： Mall et al., 2013）, CRISPR/Cas9 has rapidly become a routine technique to perform genome editing in a variety of biological systems due to its facile, robust, and multiplexable fea- tures （Hwang et al, 2013; Wang et al., 2013; Guo et al., 2014; Liu, 2017）.展开更多
Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9...Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.展开更多
A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion e...A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.展开更多
Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar inter...Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.展开更多
In recent years,genome editing with site-specific nucleases,such as ZFN（zinc finger nuclease）,TALEN（transcription activatorlike effector nucleases）,and CRISPR/Cas9（the type II bacterial clustered,regularly inters...In recent years,genome editing with site-specific nucleases,such as ZFN（zinc finger nuclease）,TALEN（transcription activatorlike effector nucleases）,and CRISPR/Cas9（the type II bacterial clustered,regularly interspaced,short palindromic repeats-associated protein 9）,has gained popularity for use in cell lines,animals,and plants（Urnov et al.,2010;Miller et al.,2011;Cong et al.展开更多
A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of he...A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of height equivalent to a theoretical plate was 25 mu m and rapid separations of small molecules such as substituted aromatic hydrocarbons and aromatic acids were achieved within five minutes.展开更多
The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice di...The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice distortion variation and quasi-particle interactions. From the low-dimensional condensed matter physics perspective, a valid mechanism is proposed to bring a type of novel channels that, under a proper external electric field, transition- forbidden triplet excitons are transformed and partially charged by charge carriers （polarons/bipolarons）, thus are able to emit light and to enhance fluorescence greatly.展开更多
The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source ...The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source rock in the Western Qaidam Depression,Qaidam Basin,NW China.Three main factors result in low TOC values of saline lacustrine source rock of the Qaidam Basin:relatively poor nutrient supply inhibits the algal bloom,too fast deposition rate causes the dilution of organic matter,and high organic matter conversion efficiency causes the low residual organic carbon.For this type of hydrogen-rich organic matter,due to the reduction of organic carbon during hydrocarbon generation,TOC needs to be restored based on maturity before evaluating organic matter abundance.The hydrocarbon generation of saline lacustrine source rocks of the Qaidam Basin is from two parts:soluble organic matter and insoluble organic matter.The soluble organic matter is inherited from organisms and preserved in saline lacustrine basins.It generates hydrocarbons during low-maturity stage,and the formed hydrocarbons are rich in complex compounds such as NOS,and undergo secondary cracking to form light components in the later stage;the hydrocarbon generation model of insoluble organic matter conforms to the traditional“Tissot”model,with an oil generation peak corresponding to Ro of 1.0%.展开更多
A family of highly bulky bis(salicylaldiminate)Co(Ⅱ)complexes bearing cavity-like conformations are disclosed herein.Due to their unique bulky nature around the cobalt atoms that are reflected from space-filling mode...A family of highly bulky bis(salicylaldiminate)Co(Ⅱ)complexes bearing cavity-like conformations are disclosed herein.Due to their unique bulky nature around the cobalt atoms that are reflected from space-filling models and the buried volume percentages,obviously longer bond distances of Co―N and Co―O are revealed from those complexes.Moreover,because of these well-protected active species,the cobalt complexes are able to catalyze 1,3-butadiene polymerization in high yields at extreme low catalyst concentrations,revealing a ultra high catalytic efficiency.At a ratio of 50000,all the complexes can afford polybutadiene with yields higher than 90%.Furthermore,the highly steric bulkiness of the ligand can also significantly enhance the thermostability of the active species.At temperature of 80-120°C,the complexes are able to successfully maintain high activities,giving polymer yields up to 90%.展开更多
A distinctive method is proposed by simply utilizing ultrasonic technique in Ti02 electrode fabrication in order to improve the optoelectronic performance of dye-sensitized solar cells （DSSCs）. Dye molecules are at ...A distinctive method is proposed by simply utilizing ultrasonic technique in Ti02 electrode fabrication in order to improve the optoelectronic performance of dye-sensitized solar cells （DSSCs）. Dye molecules are at random and single molecular state in the ultrasonic field and the ultrasonic wave favors the diffusion and adsorption processes of dye molecules. As a result, the introduction of ultrasonic technique at room temperature leads to faster and more well-distributed dye adsorption on TiO2 as well as higher cell efficiency than regular deposition, thus the fabrication time is markedly reduced. It is found that the device based on 40 kHz ultrasonic （within 1 h） with N719 exhibits a Voc of 789 mV, Jsc of 14.94 mA]cm2 and fill factor （FF） of 69.3, yielding power conversion efficiency （PCE） of 8.16%, which is higher than device regularly dyed for 12 h （PCE = 8.06%）. In addition, the DSSC devices obtain the best efficiency （PCE = 8.68%） when the ultrasonic deposition time increases to 2.5 h. The DSSCs fabricated via ultrasonic technique presents more dye loading, larger photocurrent, less charge recombination and higher photovoltage. The charge extraction and electron impedance spectroscopy （EIS） were performed to understand the influence of ultrasonic technique on the electron recombination and performance of DSSCs.展开更多
The efficiency of the photonic spin Hall effect(PSHE)has attracted increasing attention,as it plays a key role in the development of spin-selective devices.However,highly efficient enhancement of PSHE has always been ...The efficiency of the photonic spin Hall effect(PSHE)has attracted increasing attention,as it plays a key role in the development of spin-selective devices.However,highly efficient enhancement of PSHE has always been achieved at a single wavelength.Here,we propose a method to achieve highly efficient enhancement of the photonic spin Hall effect over a broadband operating wavelength by utilizing a magnetic dipole quasibounded state in the continuum(q-MDBIC)with a high refractive index.Under both horizontal and vertical polarization incidence,when the wavelength is 50.9–51.9μm and the incident angle is 0.5°–10°,the transverse shift of PSHE can reach 1.7λ–37λ,with high efficiency of more than 90%.Meanwhile,the quality(Q)factor can also be maintained around 55.Furthermore,different metasurface lattice periods can achieve different broadband PSHE,which provides favorable conditions for the control of broadband PSHE.Our work will have wide applications in devices with efficient spin selection.展开更多
Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defect...Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defects.However,the matching techniques between classical waveguides and the topological one-way waveguide deserve more attention for real-world applications.In this paper,a highly efficient conversion structure between a classical rectangular waveguide and a topological one-way waveguide is proposed and demonstrated at the microwave frequency,which efficiently converts classical guided waves to topological one-way edge states.A tapered transition is designed to match both the momentum and impedance of the classical guided waves and the topological one-way edge states.With the conversion structure,the waves generated by a point excitation source can be coupled to the topological one-way waveguide with very high coupling efficiency,which can ensure high transmission of the whole system(i.e.,from the source and the receiver).Simulation and measurement results demonstrate the proposed method.This investigation is beneficial to the applications of topological one-way waveguides and opens up a new avenue for advanced topological and classical integrated functional devices and systems.展开更多
Mosses,particularly desiccation-tolerant(DT)species,are important model organisms for studying genes involved in plant development and stress resistance.The lack of a simple and efficient stable moss transformation sy...Mosses,particularly desiccation-tolerant(DT)species,are important model organisms for studying genes involved in plant development and stress resistance.The lack of a simple and efficient stable moss transformation system has hindered progress in deciphering the genetic mechanisms underlying traits of interest in these organisms.Here,we present an Agrobacterium tumefaciens-mediated transformation system for DT mosses that uses Agrobacterium strain EHA105 harboring the binary vector pCAMBIA1301-GUS.This system achieved transformation efficiencies of 74%and 81%in Physcomitrium patens and Bryum argenteum protonemata,respectively,without the need for culture and callus formation prior to regeneration.We detected GUS enzyme activity in the regenerated transgenic moss via histochemical staining.Southern blot,PCR,and RT-qPCR analyses confirmed the presence of the GUS gene.In addition,we successfully used this system to transform wild DT Syntrichia caninervis.Furthermore,P.patens and B.argenteum transformed using this system with the stress resistance gene EsDREB from the desert plant Eremosparton songoricum(Litv.)exhibited improved salt tolerance.We thus present an efficient tool for the genetic analysis of DT moss species,paving the way for the development of stress-resistant crop cultivars.展开更多
基金funded by the National Natural Science Foundation of China (30971776)the National Transgenic Organism Research Program of China(2008ZX08010-004)
文摘Establishment of a highly efficient regeneration system for the mature embryo of wheat will provide a convenient tool for wheat tissue culture and transformation, thereby facilitating the transformation of foreign genes into wheat. By using the mature embryos derived from 20 different wheat lines including Shi 4185, Yumai 66, Lunxuan 987, CB037, Yangmai 6, Xinchun 9, Bobwhite, Han 6172, Zheng 9023, Jimai 20, Ningchun 4, and Jing 411, the effects of some factors including inoculation methods, initiating culture media, organic additives, antioxidants, and auxins on the regeneration from the explants were evaluated. The results indicated that the scraping embryo culture was better than the whole embryo culture, the Aa medium was better than the SD2 medium and dicamba was better than 2,4-D in increasing the regeneration frequency. An Adi medium was established in this study by adding silver nitrate, cysteine, ascorbic acid, dicamba, glutamine into the Aa medium at the concentration of 4,40, 100, 2, and 5 mg L^-1, respectively. By using the Adi medium and the scraping technique, the regeneration frequencies of the mature embryos of CB037, Lunxuan 987, Hart 6172, Yangmai 6, Bobwhite, Zheng 9023, Shi 4 185, and Jimai 20 became 85.6, 60,1, 46.0, 42.1,42.0, 34.0, 33.0, and 32.0%, respectively, which were about 5-8 times higher than that obtained from the conventional culture mediums and techniques. This novel regeneration system could be helpful in wheat transformation.
基金supported by Genetically Modified Breeding Major Projects(No.2016ZX08010-002-008)the National Natural Science Foundation of China(Nos.31501239 and 31401454)
文摘Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on the combination of beneficial alleles at the quantitative trait loci （QTLs）. However, the conventional cross breeding method is extremely time-consuming and laborious for pyramiding multiple QTLs. In certain cases, this approach might be technically difficult because of close linkage between genes separately responsible for desirable and undesirable traits.
基金sponsored by the National Key Basic Research Program of China(2007CB2095)
文摘Based on reserve abundance,large gas fields in China can be divided into two types：type one of high abundance large gas fields,dominated by structural gas reservoirs; type two of low abundance large gas fields,dominated by stratigraphic and lithologic gas reservoirs.The formation of these two types of large gas fields is related to the highly efficient accumulation of natural gas.The accumulation of high abundance gas fields is dependent on the rapid maturation of the source kitchen and huge residual pressure difference between the gas source kitchen and reservoir,which is the strong driving force for natural gas migration to traps.Whereas the accumulation of low abundance gas fields is more complicated,involving both volume flow charge during the burial stage and diffusion flow charge during the uplift stage,which results in large area accumulation and preservation of natural gas in low porosity and low permeability reservoirs.This conclusion should assist gas exploration in different geological settings.
文摘A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium（Ill） complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device exhibits a greenish-yellow emission with the peak at 523nm and a strong shoulder at 557nm, corresponding to Commission Internationale de l＇Eclairage coordinates of （0.38, 0.68）. The full width at half maximum of the device is 93 nm, which is broader than the fac-tris（2-phenylpyridine）iridium [Ir（ppy）3] based reference device of 78 nm. Meanwhile, a maximum current efficiency of 62.6 cd/A （47.51m/W） is obtained. This result is higher than a maximum current efficiency of 54.8 cd/A （431m/W） of the Ir（ppy）a based device. The results indicate that this new iridium complex may have potential applications in fabricating high color rendering index white organic light emitting diodes.
基金financially supported by the National Natural Science Foundation of China (No. 51708078)the Science and Technology Research Program of Chongqing Municipal Education Commission (No. KJZD-K201900502)+1 种基金the Natural Science Foundation of Chongqing (No. 2018jcyj A1040)the Innovative Research Team of Chongqing (No. CQYC201903221)。
文摘A novel SrSn(OH)_(6) photocatalyst with large plate and particle size were synthesized via a facile chemical precipitation method. The photocatalytic activity of the SrSn(OH)_(6) was evaluated by the removal of NO at ppb level under UV light irradiation. Based on the ESR measurements, SrSn(OH)_(6) photocatalyst was found to have the ability to generate the main active species of O_(2)^(·-), ^(·)OH and ^(1)O_(2) during the photocatalytic process. Moreover, SrSn(OH)_(6) photocatalyst not only exhibits high photocatalytic activity for NO removal (79.6%), but also has good stability after five cycles. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to investigate the NO_(x) transfer pathway and the intermediate products distribution during the adsorption and photocatalytic NO oxidation process. The present work not only provides an efficient material for air pollutants purification at room temperature but also in-depth understanding of the mechanism involved in the photocatalytic NO removal process.
基金supported by the grants from the National Natural Science Foundation of China (No.31101038 to M.Shao,31471360 and 31671509 to D.-L.Shi)Shandong Provincial Natural Science Foundation (ZR2017BC068 to M.Shao)
文摘Since its first application to induce mutations in mammalian cells （Cong et al., 2013： Mall et al., 2013）, CRISPR/Cas9 has rapidly become a routine technique to perform genome editing in a variety of biological systems due to its facile, robust, and multiplexable fea- tures （Hwang et al, 2013; Wang et al., 2013; Guo et al., 2014; Liu, 2017）.
基金supported by the Beijing Scholars Program[BSP041]。
文摘Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.
基金Supported by the National Natural Science Foundation of China under Grant No 11335003
文摘A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.
基金Supported by the National Natural Science Foundation of China under Grant No 91441201
文摘Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.
基金supported by the Science Research Center of the National Research Foundation of Korea (No. 2015R1A5A1009701).
文摘In recent years,genome editing with site-specific nucleases,such as ZFN（zinc finger nuclease）,TALEN（transcription activatorlike effector nucleases）,and CRISPR/Cas9（the type II bacterial clustered,regularly interspaced,short palindromic repeats-associated protein 9）,has gained popularity for use in cell lines,animals,and plants（Urnov et al.,2010;Miller et al.,2011;Cong et al.
文摘A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of height equivalent to a theoretical plate was 25 mu m and rapid separations of small molecules such as substituted aromatic hydrocarbons and aromatic acids were achieved within five minutes.
文摘The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice distortion variation and quasi-particle interactions. From the low-dimensional condensed matter physics perspective, a valid mechanism is proposed to bring a type of novel channels that, under a proper external electric field, transition- forbidden triplet excitons are transformed and partially charged by charge carriers （polarons/bipolarons）, thus are able to emit light and to enhance fluorescence greatly.
基金Supported by the PetroChina Science and Technology Project(2021DJ1808).
文摘The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source rock in the Western Qaidam Depression,Qaidam Basin,NW China.Three main factors result in low TOC values of saline lacustrine source rock of the Qaidam Basin:relatively poor nutrient supply inhibits the algal bloom,too fast deposition rate causes the dilution of organic matter,and high organic matter conversion efficiency causes the low residual organic carbon.For this type of hydrogen-rich organic matter,due to the reduction of organic carbon during hydrocarbon generation,TOC needs to be restored based on maturity before evaluating organic matter abundance.The hydrocarbon generation of saline lacustrine source rocks of the Qaidam Basin is from two parts:soluble organic matter and insoluble organic matter.The soluble organic matter is inherited from organisms and preserved in saline lacustrine basins.It generates hydrocarbons during low-maturity stage,and the formed hydrocarbons are rich in complex compounds such as NOS,and undergo secondary cracking to form light components in the later stage;the hydrocarbon generation model of insoluble organic matter conforms to the traditional“Tissot”model,with an oil generation peak corresponding to Ro of 1.0%.
基金financially supported by the National Natural Science Foundation of China(Nos.U1862206 and 21801236)。
文摘A family of highly bulky bis(salicylaldiminate)Co(Ⅱ)complexes bearing cavity-like conformations are disclosed herein.Due to their unique bulky nature around the cobalt atoms that are reflected from space-filling models and the buried volume percentages,obviously longer bond distances of Co―N and Co―O are revealed from those complexes.Moreover,because of these well-protected active species,the cobalt complexes are able to catalyze 1,3-butadiene polymerization in high yields at extreme low catalyst concentrations,revealing a ultra high catalytic efficiency.At a ratio of 50000,all the complexes can afford polybutadiene with yields higher than 90%.Furthermore,the highly steric bulkiness of the ligand can also significantly enhance the thermostability of the active species.At temperature of 80-120°C,the complexes are able to successfully maintain high activities,giving polymer yields up to 90%.
基金supported by the Science Fund for Creative Research Groups(21421004)the National Basic Research 973 Program(2013CB733700)NSFC/China(21172073,21372082,21572062 and 91233207)
文摘A distinctive method is proposed by simply utilizing ultrasonic technique in Ti02 electrode fabrication in order to improve the optoelectronic performance of dye-sensitized solar cells （DSSCs）. Dye molecules are at random and single molecular state in the ultrasonic field and the ultrasonic wave favors the diffusion and adsorption processes of dye molecules. As a result, the introduction of ultrasonic technique at room temperature leads to faster and more well-distributed dye adsorption on TiO2 as well as higher cell efficiency than regular deposition, thus the fabrication time is markedly reduced. It is found that the device based on 40 kHz ultrasonic （within 1 h） with N719 exhibits a Voc of 789 mV, Jsc of 14.94 mA]cm2 and fill factor （FF） of 69.3, yielding power conversion efficiency （PCE） of 8.16%, which is higher than device regularly dyed for 12 h （PCE = 8.06%）. In addition, the DSSC devices obtain the best efficiency （PCE = 8.68%） when the ultrasonic deposition time increases to 2.5 h. The DSSCs fabricated via ultrasonic technique presents more dye loading, larger photocurrent, less charge recombination and higher photovoltage. The charge extraction and electron impedance spectroscopy （EIS） were performed to understand the influence of ultrasonic technique on the electron recombination and performance of DSSCs.
基金supported by the National Natural Science Foundation of China(Nos.12374273,12421005,62271332,and 62275162)the Basic and Applied Basic Research Foundation of Guangdong Province(Nos.2023A1515030152)+1 种基金Hunan Provincial Major Sci-Tech Program(No.2023ZJ1010)the Open Fund Project of State Key Laboratory of Precision Measurement Technology and Instruments(No.2024PMTI04).
文摘The efficiency of the photonic spin Hall effect(PSHE)has attracted increasing attention,as it plays a key role in the development of spin-selective devices.However,highly efficient enhancement of PSHE has always been achieved at a single wavelength.Here,we propose a method to achieve highly efficient enhancement of the photonic spin Hall effect over a broadband operating wavelength by utilizing a magnetic dipole quasibounded state in the continuum(q-MDBIC)with a high refractive index.Under both horizontal and vertical polarization incidence,when the wavelength is 50.9–51.9μm and the incident angle is 0.5°–10°,the transverse shift of PSHE can reach 1.7λ–37λ,with high efficiency of more than 90%.Meanwhile,the quality(Q)factor can also be maintained around 55.Furthermore,different metasurface lattice periods can achieve different broadband PSHE,which provides favorable conditions for the control of broadband PSHE.Our work will have wide applications in devices with efficient spin selection.
基金supported by the National Natural Science Foundation of China(No.62171082)the Natural Science Foundation of Sichuan Province(No.2022NSFSC0483)。
文摘Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defects.However,the matching techniques between classical waveguides and the topological one-way waveguide deserve more attention for real-world applications.In this paper,a highly efficient conversion structure between a classical rectangular waveguide and a topological one-way waveguide is proposed and demonstrated at the microwave frequency,which efficiently converts classical guided waves to topological one-way edge states.A tapered transition is designed to match both the momentum and impedance of the classical guided waves and the topological one-way edge states.With the conversion structure,the waves generated by a point excitation source can be coupled to the topological one-way waveguide with very high coupling efficiency,which can ensure high transmission of the whole system(i.e.,from the source and the receiver).Simulation and measurement results demonstrate the proposed method.This investigation is beneficial to the applications of topological one-way waveguides and opens up a new avenue for advanced topological and classical integrated functional devices and systems.
基金supported by the Leading Talents in Technological Innovation programme(2022TSYCLJ0049)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502030403).
文摘Mosses,particularly desiccation-tolerant(DT)species,are important model organisms for studying genes involved in plant development and stress resistance.The lack of a simple and efficient stable moss transformation system has hindered progress in deciphering the genetic mechanisms underlying traits of interest in these organisms.Here,we present an Agrobacterium tumefaciens-mediated transformation system for DT mosses that uses Agrobacterium strain EHA105 harboring the binary vector pCAMBIA1301-GUS.This system achieved transformation efficiencies of 74%and 81%in Physcomitrium patens and Bryum argenteum protonemata,respectively,without the need for culture and callus formation prior to regeneration.We detected GUS enzyme activity in the regenerated transgenic moss via histochemical staining.Southern blot,PCR,and RT-qPCR analyses confirmed the presence of the GUS gene.In addition,we successfully used this system to transform wild DT Syntrichia caninervis.Furthermore,P.patens and B.argenteum transformed using this system with the stress resistance gene EsDREB from the desert plant Eremosparton songoricum(Litv.)exhibited improved salt tolerance.We thus present an efficient tool for the genetic analysis of DT moss species,paving the way for the development of stress-resistant crop cultivars.
