Porous aromatic framework 1(PAF-1)is an extremely representative nanoporous organic framework owing to its high stability and exceptionally high surface area.Currently,the synthesis of PAF-1 is catalyzed by the Ni(COD...Porous aromatic framework 1(PAF-1)is an extremely representative nanoporous organic framework owing to its high stability and exceptionally high surface area.Currently,the synthesis of PAF-1 is catalyzed by the Ni(COD)2/COD/bpy system,suffering from great instability and high cost.Herein,we developed an in situ reduction of the Ni(II)catalytic system to synthesize PAF-1 in low cost and high yield.The active Ni(0)species produced from the NiCl_(2)/bpy/NaI/Mg catalyst system can effectively catalyze homocoupling of tetrakis(4-bromophenyl)methane at the room temperature to form PAF-1 with high Brunauer-Emmett-Teller(BET)-specific surface area up to 4948 m^(2) g^(−1)(Langmuir surface area,6785 m2 g−1).The possible halogen exchange and dehalogenation coupling mechanisms for this new catalytic process in PAF's synthesis are discussed in detail.The efficiency and universality of this innovative catalyst system have also been demonstrated in other PAFs'synthesis.This work provides a cheap,facile,and efficient method for scalable synthesis of PAFs and explores their application for high-pressure storage of Xe and Kr.展开更多
The green disposal of tailings solid waste is a problem to be solved in mine production.Cemented tailings filling stoping method can realize the dual goals of solid waste resource utilization and mined-out area reduct...The green disposal of tailings solid waste is a problem to be solved in mine production.Cemented tailings filling stoping method can realize the dual goals of solid waste resource utilization and mined-out area reduction.However,the volume of the mined-out area of the open-pit method is larger than the filling capacity,resulting in the complex stratification of the underground backfill,and the strength of the backfill cannot meet the requirements.In this paper,according to the delamination situation,the specimens of horizontal and inclination angle layered cemented tailings backfill(LCTB)is made for a uniaxial compression test,and the failure process of delamination backfill is reduced by PFC.The results show that the corresponding reduction factorφof horizontal LCTB is 0.560–0.932,and the correspondingφvalue of inclination angle LCTB is 0.338–0.772.The failure mode of backfill in different layers is mainly manifested as a tensile failure.The PFC numerical simulation results are consistent with laboratory test results,which verifies the correctness of backfill failure.The research results provide a reliable theoretical basis for the strength design of backfill in goaf,which is of great significance for solid waste utilization and environmental protection.展开更多
Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses sign...Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses significant carbon footprint to the environment.Clean adipic acid synthesis methods using a heterogeneous catalyst with H2O2 as oxidant and water as solvent have potential advantages of low catalyst cost,easy synthesis and recovery,cleanness and environmental protection.In this work,hexagonal mesoporous silicate materials were synthesized by a sol–gel method and evaluated for cyclohexanol/cyclohexanone oxidation to adipic acid.The physical and chemical properties of Fe-HMS were characterized by XRD,HR-TEM,BET and UV–Vis.The experimental results showed that Fe-HMS materials show pore sizes ranging from 2–3 nm.W-and Mo-based polyoxometalates were also evaluated and compared to the Fe-based HMS catalysts.To improve the adipic acid yield,the influence of the transition metal as well as the effect of metal loading,reaction temperature and catalyst amount on the catalytic performances of Fe-HMS have been investigated in details.When Si/Fe atomic ratio=100,Fe-HMS catalyst shows the highest activity,with a cyclohexanone conversion of 92.3%and adipic acid selectivity of 29.4%.The reaction pathway of cyclohexanone oxidation was further proposed based on experimental data.展开更多
On-line chatter detection can avoid unstable cutting through monitoring the machining process.In order to identify chatter in a timely manner,an improved Support Vector Machine(SVM)is developed in this paper,based on ...On-line chatter detection can avoid unstable cutting through monitoring the machining process.In order to identify chatter in a timely manner,an improved Support Vector Machine(SVM)is developed in this paper,based on extracted features.In the SVM model,the penalty factor(e)and the core parameter(g)have important influence on the classification,more than from Kernel Functions(KFs).Hence,first the classification results are conducted using different KFs.Then two methods are presented for exploring the best parameters.The chatter identification results show that the Genetic Algorithm(GA)approach is more suitable for deciding the parameters than the Grid Explore(GE)approach.展开更多
To provide an evidence of natural gas hydrate occurrence state,a series of experiments on multiple growth and dissociation of 90.0%methane/10.0%propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediment...To provide an evidence of natural gas hydrate occurrence state,a series of experiments on multiple growth and dissociation of 90.0%methane/10.0%propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediments for morphology observation via a visible jacketed-reactor.The gas hydrate crystals were observed to form and grow on the surface of sediments at the initial growth.During the thermal decomposition,gas and liquid products had an unceasingly impact on the sediments,then gas/liquid–solid migration occurred,and a large number of cavitation appeared.In the later growth and dissociation experiments,the gas hydrate particles were in suspension or supporting states in the interstitial pore space between the sediment particles,indicating that the gas hydrate displayed a pore-filling characteristics.Through analyzing the distribution of gas hydrates and bubbles,it was found that the amount of gas hydrates distributed in the sediments was improved with multiple growth-dissociation cycle proceedings.Gas migration enhanced the sediment movement,which led to the appearance of the increasing quantity of gas bubbles in the sediments during cycles.Salts affected the growth of the gas hydrates and the migration of sediment grains,which also restricted the accumulation of gas bubbles in the sediments.According to the Raman analysis,the results showed that sII hydrates were formed for CH4 and C3H8 gas mixtures in different sediments and solutions with hydration number of 5.84–6.53.The Salt restricted the access of gas into the hydrate cages.展开更多
Semi-artificial photosynthesis interfacing catalytic protein machinery with synthetic photocatalysts exhibits great potential in solar-to-chemical energy conversion. However, characterizing and manipulating the molecu...Semi-artificial photosynthesis interfacing catalytic protein machinery with synthetic photocatalysts exhibits great potential in solar-to-chemical energy conversion. However, characterizing and manipulating the molecular integration structure at the biotic-abiotic interface remain a challenging task. Herein,the biointerface molecular integration details of photosystem II(PSII)-semiconductor hybrids, including the PSII orientation, interfacial microdomains, and overall structure modulation, are systematically interrogated by lysine reactivity profiling mass spectrometry. We demonstrate the semiconductor surface biocompatibility is essential to the PSII self-assembly with uniform orientation and electroactive structure.Highly directional localization of PSII onto more hydrophilic Ru/Sr Ti O_(3):Rh surface exhibits less disturbance on PSII structure and electron transfer chain, beneficial to the high water splitting activity.Further, rational modification of hydrophobic Ru_(2)S_(3)/Cd S surface with biocompatible protamine can improve the hybrid O_(2)-evolving activity 83.3%. Our results provide the mechanistic understanding to the structure–activity relationship of PSII-semiconductor hybrids and contribute to their rational design in the future.展开更多
The principle aim of this paper is to explore the existence of periodic solution of neural networks model with neutral delay. Sufficient and realistic conditions are obtained by means of an abstract continuous theorem...The principle aim of this paper is to explore the existence of periodic solution of neural networks model with neutral delay. Sufficient and realistic conditions are obtained by means of an abstract continuous theorem of k-set contractive operator and some analysis technique.展开更多
Chaotic synchronization is the key technology of secure communication. In this paper, ?an impulsive control method for chaotic synchronization of two coupled Lorenz chaotic system was proposed. The global asymptotic s...Chaotic synchronization is the key technology of secure communication. In this paper, ?an impulsive control method for chaotic synchronization of two coupled Lorenz chaotic system was proposed. The global asymptotic synchronization of two Lorenz systems was realized by using the linear error feedback of the state variables of the drive system and the response system as impulsive control signal. Based on stability theory of impulsive differential equation, conditions were obtained to guarantee the global asymptotic synchronization of two Lorenz systems. The theory analysis and computer simulation results validated its effectiveness.展开更多
Densely populated coasts are vulnerable to storm damage. Episodic storm-induced redistribution of coastal sediment is known to have major geological and ecological implications [1,2], but little is known about storm-d...Densely populated coasts are vulnerable to storm damage. Episodic storm-induced redistribution of coastal sediment is known to have major geological and ecological implications [1,2], but little is known about storm-driven delta erosion and longshore sediment transport. The Yangtze (Changjiang) Delta and Zhejiang–Fujian coasts (Fig. S1 online) are among the world’s largest coastal depositional systems, and play an important role in supporting China’s socioeconomic development [3,4].展开更多
The Metaverse is the digitization of the real world,supported by big data,AI,5G,cloud computing,blockchain,encryption algorithm,perception technology,digital twin,virtual engine,and other technologies that interact wi...The Metaverse is the digitization of the real world,supported by big data,AI,5G,cloud computing,blockchain,encryption algorithm,perception technology,digital twin,virtual engine,and other technologies that interact with human behavior and thoughts in avatars through digital identity.Cracking the trust problem brought by the avatar depends on the privacy security and authentication technology for individuals using digital identities to enter the Metaverse.To accomplish personal domination of the avatar,metaverse users need privacy data feeding and emotion projection.They must be equipped with proprietary algorithms to process and analyze the complex data generated in adaptive interactions,which challenges the privacy security of user data in the Metaverse.Distinguishing the significance of different identifiers in personal identity generation while imposing different behavioral regulatory requirements on data processing levels may better balance the relationship between personal privacy security and digital identity protection and data utilization in the Metaverse.In response to digital identity issues,there is an objective need to establish a unified digital identity authentication system to gain the general trust of society.Further,the remedies for a right to personality can be applied to the scenario of unlawful infringement of digital identity and privacy security.展开更多
The phase-sensitive time-domain reflectometer [φ-OTDR] has been popularly used for events detection over a long period of time.In this study,the events classification methods based on convolutional neural networks [C...The phase-sensitive time-domain reflectometer [φ-OTDR] has been popularly used for events detection over a long period of time.In this study,the events classification methods based on convolutional neural networks [CNNs] with different features,i.e.,the temporal-spatial features and time-frequency features,are compared and analyzed comprehensively inφ-OTDR.The developed CNNs aim at distinguishing three typical events:wind blowing,knocking,and background noise.The classification accuracy based on temporal-spatial images is higher than that based on time-frequency images[99.49% versus 98.23%).The work here sets a meaningful reference for feature extraction and application in the pattern recognition of φ-OTDR.展开更多
Temperature sensing is essential for human health monitoring.High-sensitivity(>1 nm∕℃)fiber sensors always require long interference paths and temperature-sensitive materials,leading to a long sensor and thus slo...Temperature sensing is essential for human health monitoring.High-sensitivity(>1 nm∕℃)fiber sensors always require long interference paths and temperature-sensitive materials,leading to a long sensor and thus slow response(6–14 s).To date,it is still challenging for a fiber optic temperature sensor to have an ultrafast(~ms)response simultaneously with high sensitivity.Here,a side-polished single-mode/hollow/single-mode fiber(SPSHSF)structure is proposed to meet the challenge by using the length-independent sensitivity of an anti-resonant reflecting optical waveguide mechanism.With a polydimethylsiloxane filled sub-nanoliter volume cavity in the SP-SHSF,the SP-SHSF exhibits a high temperature sensitivity of 4.223 nm/℃ with a compact length of 1.6 mm,allowing an ultrafast response(16 ms)and fast recovery time(176 ms).The figure of merit(FOM),defined as the absolute ratio of sensitivity to response time,is proposed to assess the comprehensive performance of the sensor.The FOM of the proposed sensor reaches up to 263.94(nm/℃)∕s,which is more than two to three orders of magnitude higher than those of other temperature fiber optic sensors reported previously.Additionally,a threemonth cycle test shows that the sensor is highly robust,with excellent reversibility and accuracy,allowing it to be incorporated with a wearable face mask for detecting temperature changes during human breathing.The high FOM and high stability of the proposed sensing fiber structure provide an excellent opportunity to develop both ultrafast and highly sensitive fiber optic sensors for wearable respiratory monitoring and contactless in vitro detection.展开更多
代谢综合征是一种全球性的慢性流行病,其发病机理由遗传与环境等因素共同决定。表观遗传修饰是在基因的核苷酸序列不发生改变的情况下,通过可遗传的变化调控基因表达。近年来研究发现,表观遗传修饰能够应答于环境因素、调控基因表达和...代谢综合征是一种全球性的慢性流行病,其发病机理由遗传与环境等因素共同决定。表观遗传修饰是在基因的核苷酸序列不发生改变的情况下,通过可遗传的变化调控基因表达。近年来研究发现,表观遗传修饰能够应答于环境因素、调控基因表达和信号转导进程。其中,染色质重塑复合物SWI/SNF(SWItch/Sucrose non fermentable,SWI/SNF)关键亚基Baf60a,在维持机体能量代谢稳态过程中发挥着重要作用。文中重点阐述了生理和病理状态下,Baf60a维持机体脂质代谢、胆固醇代谢、尿素循环及代谢节律性稳态的分子机制。深入探讨以Baf60a为基点的能量代谢调控网络,有望为代谢综合征的改善和治疗提供潜在药物治疗靶点和扎实的研究依据。展开更多
The MADS-box genes encode a large family of transcription factors having diverse roles in plant development. The SQUAMOSA (SQUA)/APETALA1 (AP1)/FRUITFULL (FUL) subfamily genes are essential regulators of floral ...The MADS-box genes encode a large family of transcription factors having diverse roles in plant development. The SQUAMOSA (SQUA)/APETALA1 (AP1)/FRUITFULL (FUL) subfamily genes are essential regulators of floral transition and floral organ identity. Here we cloned two MADS-box genes, GhMADS22 and GhMADS23, belonging to the SQUA/AP1/FUL subgroup from Gossypium hirsutum L. Phylogenetic analysis and sequence alignment showed that GhMAD$22 and GhMADS23 belonged to the euFUL and euAP1 subclades, respectively. The two genes both had eight exons and seven introns from the start codon to the stop codon according to the alignment between the obtained cDNA sequence and the Gossypium raimondii L. genome sequence. Expression profile analysis showed that GhMADS22 and GhMADS23 were highly expressed in developing shoot apices, bracts, and sepals. Gibberellic acid promoted GhMADS22 and GhMADS23 expression in the shoot apex. Transgenic Arabidopsis lines overexpressing 35S::GhMADS22 had abnormal flowers and bolted earlier than wild type under long-day conditions (16 h light/8 h dark). Moreover, GhMADS22 over- expression delayed floral organ senescence and abscission and it could also respond to abscisic acid. In summary, GhMADS22 may have functions in promoting flowering, improving resistance and delaying senescence for cotton and thus it may be a candidate target for promoting early-maturation in cotton breeding.展开更多
Polycystic ovary syndrome(PCOS)is a heterogeneous disorder with evidence of polygenetic components,and obesity may be a risk factor for hyperandrogen ism.Previous studies have shown that LHCGR is en riched in the ovar...Polycystic ovary syndrome(PCOS)is a heterogeneous disorder with evidence of polygenetic components,and obesity may be a risk factor for hyperandrogen ism.Previous studies have shown that LHCGR is en riched in the ovary and LHCGR deficiency causes infertility without typical PCOS phenotypes.ALMS1 is implicated in obesity and hyperandrogenism,the common phenotypes among PCOS patients.Through whole-exome sequencing of 22 PCOS families and targeted candidate gene sequencing of additional 65 sporadic PCOS patients,we identified potential causative mutations in LHCGR and ALMS1 in a sibling-pair PCOS family and three sporadic PCOS patients.The expression of LHCGRL638 P in granulosa-like tumor cell line(KGN)cells promoted cyclic adenosine monophosphate production and granulosa cell proliferation,indicating that LHCGRL638 P is an activating mutation.Lhcgr~(L642 P/L642 P)mice showed an irregular estrous cycle,reduced follicles with dynamic folliculogenesis,and increased testosterone(T),estradiol(E2),and dehydroepiandrosterone.Lhcgr~(+/L642 P)AIms1~(+/PB)mice displayed increased T and E2 but decreased late secondary and preovulatory follicles.We showed that activating mutation of LHCGR likely plays important roles in the pathophysiology of PCOS involving abnormal reproductive physiology,whereas ALMS1 deficiency may promote anovulatory infertility via elevated androgens,suggesting that the disturbed LHCGR and ALMS1 cooperatively induce PCOS phenotypes,characterized as anovulation and hyperandrogenemia frequently observed in PCOS patients with obesity.展开更多
Upland cotton (Gossypium hirsutum L.) shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line...Upland cotton (Gossypium hirsutum L.) shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line could substantially reduce the cost of hybrid seed production in upland cotton. Such a mutant with virescent marker was found by space mutation in near-earth orbit and its traits had been stable after 4 years of selection in Anyang and Sanya, China. This mutant was fertile with an 11-12.5 h photoperiod when the temperature was higher than 21.5 ℃ and was sterile with a 13-14.5 h photoperiod. Genetic analysis indicated that both traits were controlled by a single recessive gene or two closely linked genes. Also, the cytological observations and transcriptome profiling analysis showed that the degradation of pollen grain cytoplasm should be the primary reason why the mutant line were male sterile under long-day conditions.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:21975096,22178280Key Laboratory of Nuclear Data Foundation,Grant/Award Number:JCKY2021201C151Young Talent Support Plan,Grant/Award Number:HG6J001。
文摘Porous aromatic framework 1(PAF-1)is an extremely representative nanoporous organic framework owing to its high stability and exceptionally high surface area.Currently,the synthesis of PAF-1 is catalyzed by the Ni(COD)2/COD/bpy system,suffering from great instability and high cost.Herein,we developed an in situ reduction of the Ni(II)catalytic system to synthesize PAF-1 in low cost and high yield.The active Ni(0)species produced from the NiCl_(2)/bpy/NaI/Mg catalyst system can effectively catalyze homocoupling of tetrakis(4-bromophenyl)methane at the room temperature to form PAF-1 with high Brunauer-Emmett-Teller(BET)-specific surface area up to 4948 m^(2) g^(−1)(Langmuir surface area,6785 m2 g−1).The possible halogen exchange and dehalogenation coupling mechanisms for this new catalytic process in PAF's synthesis are discussed in detail.The efficiency and universality of this innovative catalyst system have also been demonstrated in other PAFs'synthesis.This work provides a cheap,facile,and efficient method for scalable synthesis of PAFs and explores their application for high-pressure storage of Xe and Kr.
基金supported by the National Natural Science Foundation of China(No.51834001).
文摘The green disposal of tailings solid waste is a problem to be solved in mine production.Cemented tailings filling stoping method can realize the dual goals of solid waste resource utilization and mined-out area reduction.However,the volume of the mined-out area of the open-pit method is larger than the filling capacity,resulting in the complex stratification of the underground backfill,and the strength of the backfill cannot meet the requirements.In this paper,according to the delamination situation,the specimens of horizontal and inclination angle layered cemented tailings backfill(LCTB)is made for a uniaxial compression test,and the failure process of delamination backfill is reduced by PFC.The results show that the corresponding reduction factorφof horizontal LCTB is 0.560–0.932,and the correspondingφvalue of inclination angle LCTB is 0.338–0.772.The failure mode of backfill in different layers is mainly manifested as a tensile failure.The PFC numerical simulation results are consistent with laboratory test results,which verifies the correctness of backfill failure.The research results provide a reliable theoretical basis for the strength design of backfill in goaf,which is of great significance for solid waste utilization and environmental protection.
基金supported by the National Natural Science Foundation of China(21473073,21473074)‘‘13th Five-Year’’ Science and Technology Research of the Education Department of Jilin Province(2016403)+1 种基金the Development Project of Science and Technology of Jilin Province(20170101171JC,20180201068SF)the Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(201703)~~
基金supported by the National Natural Science Foundation(21706290)Natural Science Foundation of Shandong Province(ZR2017MB004,ZR2017BB007)+5 种基金Postdoctoral Research Funding of Shandong Province(201703016)Fundamental Research Funding of Qingdao(17-1-1-67-jch,17-1-1-80-jch)Qingdao Postdoctoral Research Funding(BY20170210)“the Fundamental Research Funds for the Central Universities”(18CX02145A,17CX02017A)new faculty start-up funding from China University of Petroleum(YJ201601058)China Postdoctoral Science Foundation(2017M612374)。
文摘Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses significant carbon footprint to the environment.Clean adipic acid synthesis methods using a heterogeneous catalyst with H2O2 as oxidant and water as solvent have potential advantages of low catalyst cost,easy synthesis and recovery,cleanness and environmental protection.In this work,hexagonal mesoporous silicate materials were synthesized by a sol–gel method and evaluated for cyclohexanol/cyclohexanone oxidation to adipic acid.The physical and chemical properties of Fe-HMS were characterized by XRD,HR-TEM,BET and UV–Vis.The experimental results showed that Fe-HMS materials show pore sizes ranging from 2–3 nm.W-and Mo-based polyoxometalates were also evaluated and compared to the Fe-based HMS catalysts.To improve the adipic acid yield,the influence of the transition metal as well as the effect of metal loading,reaction temperature and catalyst amount on the catalytic performances of Fe-HMS have been investigated in details.When Si/Fe atomic ratio=100,Fe-HMS catalyst shows the highest activity,with a cyclohexanone conversion of 92.3%and adipic acid selectivity of 29.4%.The reaction pathway of cyclohexanone oxidation was further proposed based on experimental data.
文摘On-line chatter detection can avoid unstable cutting through monitoring the machining process.In order to identify chatter in a timely manner,an improved Support Vector Machine(SVM)is developed in this paper,based on extracted features.In the SVM model,the penalty factor(e)and the core parameter(g)have important influence on the classification,more than from Kernel Functions(KFs).Hence,first the classification results are conducted using different KFs.Then two methods are presented for exploring the best parameters.The chatter identification results show that the Genetic Algorithm(GA)approach is more suitable for deciding the parameters than the Grid Explore(GE)approach.
基金Supported by the National Key Research and Development Program(2016YFC0304006,2017YFC0307302,2017YFC0307303)the National Natural Science Foundation of China(51576069,51876069)+1 种基金the China Postdoctoral Science Foundation(2018M633052)the Fundamental Research Funds for the Central Universities(D2182630)
文摘To provide an evidence of natural gas hydrate occurrence state,a series of experiments on multiple growth and dissociation of 90.0%methane/10.0%propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediments for morphology observation via a visible jacketed-reactor.The gas hydrate crystals were observed to form and grow on the surface of sediments at the initial growth.During the thermal decomposition,gas and liquid products had an unceasingly impact on the sediments,then gas/liquid–solid migration occurred,and a large number of cavitation appeared.In the later growth and dissociation experiments,the gas hydrate particles were in suspension or supporting states in the interstitial pore space between the sediment particles,indicating that the gas hydrate displayed a pore-filling characteristics.Through analyzing the distribution of gas hydrates and bubbles,it was found that the amount of gas hydrates distributed in the sediments was improved with multiple growth-dissociation cycle proceedings.Gas migration enhanced the sediment movement,which led to the appearance of the increasing quantity of gas bubbles in the sediments during cycles.Salts affected the growth of the gas hydrates and the migration of sediment grains,which also restricted the accumulation of gas bubbles in the sediments.According to the Raman analysis,the results showed that sII hydrates were formed for CH4 and C3H8 gas mixtures in different sediments and solutions with hydration number of 5.84–6.53.The Salt restricted the access of gas into the hydrate cages.
基金the financial supported by National Key R&D Program of China,China(2019YFE0119300)the National Natural Science Foundation of China,China(32088101,91853101,and 22075280)+2 种基金the Original Innovation Project of CAS,China(ZDBSLY-SLH032)the Excellent Young Scientist Grant of Liaoning Province,China(2019-YQ-07)the grant from DICP(DICPI202007)。
文摘Semi-artificial photosynthesis interfacing catalytic protein machinery with synthetic photocatalysts exhibits great potential in solar-to-chemical energy conversion. However, characterizing and manipulating the molecular integration structure at the biotic-abiotic interface remain a challenging task. Herein,the biointerface molecular integration details of photosystem II(PSII)-semiconductor hybrids, including the PSII orientation, interfacial microdomains, and overall structure modulation, are systematically interrogated by lysine reactivity profiling mass spectrometry. We demonstrate the semiconductor surface biocompatibility is essential to the PSII self-assembly with uniform orientation and electroactive structure.Highly directional localization of PSII onto more hydrophilic Ru/Sr Ti O_(3):Rh surface exhibits less disturbance on PSII structure and electron transfer chain, beneficial to the high water splitting activity.Further, rational modification of hydrophobic Ru_(2)S_(3)/Cd S surface with biocompatible protamine can improve the hybrid O_(2)-evolving activity 83.3%. Our results provide the mechanistic understanding to the structure–activity relationship of PSII-semiconductor hybrids and contribute to their rational design in the future.
文摘The principle aim of this paper is to explore the existence of periodic solution of neural networks model with neutral delay. Sufficient and realistic conditions are obtained by means of an abstract continuous theorem of k-set contractive operator and some analysis technique.
文摘Chaotic synchronization is the key technology of secure communication. In this paper, ?an impulsive control method for chaotic synchronization of two coupled Lorenz chaotic system was proposed. The global asymptotic synchronization of two Lorenz systems was realized by using the linear error feedback of the state variables of the drive system and the response system as impulsive control signal. Based on stability theory of impulsive differential equation, conditions were obtained to guarantee the global asymptotic synchronization of two Lorenz systems. The theory analysis and computer simulation results validated its effectiveness.
基金supported by the National Key Research and Development Program of China (2016YFE0133700)the National Natural Science Foundation of China (42106167 and42076170)。
文摘Densely populated coasts are vulnerable to storm damage. Episodic storm-induced redistribution of coastal sediment is known to have major geological and ecological implications [1,2], but little is known about storm-driven delta erosion and longshore sediment transport. The Yangtze (Changjiang) Delta and Zhejiang–Fujian coasts (Fig. S1 online) are among the world’s largest coastal depositional systems, and play an important role in supporting China’s socioeconomic development [3,4].
基金supported by the 2021 National Social Sciencetitled“Research on the Legal Risks and Prevention of China’s Social Media Platforms Operating in the United States”(21BXW040)
文摘The Metaverse is the digitization of the real world,supported by big data,AI,5G,cloud computing,blockchain,encryption algorithm,perception technology,digital twin,virtual engine,and other technologies that interact with human behavior and thoughts in avatars through digital identity.Cracking the trust problem brought by the avatar depends on the privacy security and authentication technology for individuals using digital identities to enter the Metaverse.To accomplish personal domination of the avatar,metaverse users need privacy data feeding and emotion projection.They must be equipped with proprietary algorithms to process and analyze the complex data generated in adaptive interactions,which challenges the privacy security of user data in the Metaverse.Distinguishing the significance of different identifiers in personal identity generation while imposing different behavioral regulatory requirements on data processing levels may better balance the relationship between personal privacy security and digital identity protection and data utilization in the Metaverse.In response to digital identity issues,there is an objective need to establish a unified digital identity authentication system to gain the general trust of society.Further,the remedies for a right to personality can be applied to the scenario of unlawful infringement of digital identity and privacy security.
基金supported by the Fundamental Research Funds for the Central Universities(No.FRF-TP-20-067A1Z)。
文摘The phase-sensitive time-domain reflectometer [φ-OTDR] has been popularly used for events detection over a long period of time.In this study,the events classification methods based on convolutional neural networks [CNNs] with different features,i.e.,the temporal-spatial features and time-frequency features,are compared and analyzed comprehensively inφ-OTDR.The developed CNNs aim at distinguishing three typical events:wind blowing,knocking,and background noise.The classification accuracy based on temporal-spatial images is higher than that based on time-frequency images[99.49% versus 98.23%).The work here sets a meaningful reference for feature extraction and application in the pattern recognition of φ-OTDR.
基金National Key Research and Development Program of China(2021YFB2800801)National Natural Science Foundation of China(12174155,12174156,61675092,62105125)+4 种基金Natural Science Foundation of Guangdong Province for Distinguished Young Scholars(2020B1515020024)Key-Area Research and Development Program of Guangdong Province(2019B010138004)Aeronautical Science Foundation of China(201708W4001,201808W4001)Special Project in Key Fields of the Higher Education Institutions of Guangdong Province(2020ZDZX3022)Project of STRPAT of EC Laboratory(ZHD201902)。
文摘Temperature sensing is essential for human health monitoring.High-sensitivity(>1 nm∕℃)fiber sensors always require long interference paths and temperature-sensitive materials,leading to a long sensor and thus slow response(6–14 s).To date,it is still challenging for a fiber optic temperature sensor to have an ultrafast(~ms)response simultaneously with high sensitivity.Here,a side-polished single-mode/hollow/single-mode fiber(SPSHSF)structure is proposed to meet the challenge by using the length-independent sensitivity of an anti-resonant reflecting optical waveguide mechanism.With a polydimethylsiloxane filled sub-nanoliter volume cavity in the SP-SHSF,the SP-SHSF exhibits a high temperature sensitivity of 4.223 nm/℃ with a compact length of 1.6 mm,allowing an ultrafast response(16 ms)and fast recovery time(176 ms).The figure of merit(FOM),defined as the absolute ratio of sensitivity to response time,is proposed to assess the comprehensive performance of the sensor.The FOM of the proposed sensor reaches up to 263.94(nm/℃)∕s,which is more than two to three orders of magnitude higher than those of other temperature fiber optic sensors reported previously.Additionally,a threemonth cycle test shows that the sensor is highly robust,with excellent reversibility and accuracy,allowing it to be incorporated with a wearable face mask for detecting temperature changes during human breathing.The high FOM and high stability of the proposed sensing fiber structure provide an excellent opportunity to develop both ultrafast and highly sensitive fiber optic sensors for wearable respiratory monitoring and contactless in vitro detection.
文摘代谢综合征是一种全球性的慢性流行病,其发病机理由遗传与环境等因素共同决定。表观遗传修饰是在基因的核苷酸序列不发生改变的情况下,通过可遗传的变化调控基因表达。近年来研究发现,表观遗传修饰能够应答于环境因素、调控基因表达和信号转导进程。其中,染色质重塑复合物SWI/SNF(SWItch/Sucrose non fermentable,SWI/SNF)关键亚基Baf60a,在维持机体能量代谢稳态过程中发挥着重要作用。文中重点阐述了生理和病理状态下,Baf60a维持机体脂质代谢、胆固醇代谢、尿素循环及代谢节律性稳态的分子机制。深入探讨以Baf60a为基点的能量代谢调控网络,有望为代谢综合征的改善和治疗提供潜在药物治疗靶点和扎实的研究依据。
基金supported by the earmarked fund for China Agriculture Research System(CARS-18)the National Hightech R&D Program of China(no.2011AA10A102)
文摘The MADS-box genes encode a large family of transcription factors having diverse roles in plant development. The SQUAMOSA (SQUA)/APETALA1 (AP1)/FRUITFULL (FUL) subfamily genes are essential regulators of floral transition and floral organ identity. Here we cloned two MADS-box genes, GhMADS22 and GhMADS23, belonging to the SQUA/AP1/FUL subgroup from Gossypium hirsutum L. Phylogenetic analysis and sequence alignment showed that GhMAD$22 and GhMADS23 belonged to the euFUL and euAP1 subclades, respectively. The two genes both had eight exons and seven introns from the start codon to the stop codon according to the alignment between the obtained cDNA sequence and the Gossypium raimondii L. genome sequence. Expression profile analysis showed that GhMADS22 and GhMADS23 were highly expressed in developing shoot apices, bracts, and sepals. Gibberellic acid promoted GhMADS22 and GhMADS23 expression in the shoot apex. Transgenic Arabidopsis lines overexpressing 35S::GhMADS22 had abnormal flowers and bolted earlier than wild type under long-day conditions (16 h light/8 h dark). Moreover, GhMADS22 over- expression delayed floral organ senescence and abscission and it could also respond to abscisic acid. In summary, GhMADS22 may have functions in promoting flowering, improving resistance and delaying senescence for cotton and thus it may be a candidate target for promoting early-maturation in cotton breeding.
基金jointly supported by the National Key Research and Development Program of China(2018YFC1002104 to L.W.,2018YFC1004904 to B.-L.W.and J.F.,2016YFC1000500 to H.Y.W.and W.F.T.)the National Natural Science Foundation of China([81930036,31521003,31771669]to H.Y.W.)+1 种基金the Commission for Science and Technology of Shanghai Municipality(17JC1400902to H.Y.W.)the MDA-CHB Research Grant to B.-L.W。
文摘Polycystic ovary syndrome(PCOS)is a heterogeneous disorder with evidence of polygenetic components,and obesity may be a risk factor for hyperandrogen ism.Previous studies have shown that LHCGR is en riched in the ovary and LHCGR deficiency causes infertility without typical PCOS phenotypes.ALMS1 is implicated in obesity and hyperandrogenism,the common phenotypes among PCOS patients.Through whole-exome sequencing of 22 PCOS families and targeted candidate gene sequencing of additional 65 sporadic PCOS patients,we identified potential causative mutations in LHCGR and ALMS1 in a sibling-pair PCOS family and three sporadic PCOS patients.The expression of LHCGRL638 P in granulosa-like tumor cell line(KGN)cells promoted cyclic adenosine monophosphate production and granulosa cell proliferation,indicating that LHCGRL638 P is an activating mutation.Lhcgr~(L642 P/L642 P)mice showed an irregular estrous cycle,reduced follicles with dynamic folliculogenesis,and increased testosterone(T),estradiol(E2),and dehydroepiandrosterone.Lhcgr~(+/L642 P)AIms1~(+/PB)mice displayed increased T and E2 but decreased late secondary and preovulatory follicles.We showed that activating mutation of LHCGR likely plays important roles in the pathophysiology of PCOS involving abnormal reproductive physiology,whereas ALMS1 deficiency may promote anovulatory infertility via elevated androgens,suggesting that the disturbed LHCGR and ALMS1 cooperatively induce PCOS phenotypes,characterized as anovulation and hyperandrogenemia frequently observed in PCOS patients with obesity.
基金supported by the National Hi-Tech R&D Program of China(2011AA10A102)the National Basic Research Program of China(2010CB126006)
文摘Upland cotton (Gossypium hirsutum L.) shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line could substantially reduce the cost of hybrid seed production in upland cotton. Such a mutant with virescent marker was found by space mutation in near-earth orbit and its traits had been stable after 4 years of selection in Anyang and Sanya, China. This mutant was fertile with an 11-12.5 h photoperiod when the temperature was higher than 21.5 ℃ and was sterile with a 13-14.5 h photoperiod. Genetic analysis indicated that both traits were controlled by a single recessive gene or two closely linked genes. Also, the cytological observations and transcriptome profiling analysis showed that the degradation of pollen grain cytoplasm should be the primary reason why the mutant line were male sterile under long-day conditions.