Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3...Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.展开更多
Recently, Quality of Experience (QoE) of voice service has been paid more attentions because it represents the performance of voice service subjectively perceived by the end users. And speech quality is commonly used ...Recently, Quality of Experience (QoE) of voice service has been paid more attentions because it represents the performance of voice service subjectively perceived by the end users. And speech quality is commonly used to measure the QoE value. In this paper, a speech quality assessment algorithm is proposed for GSM network, aiming to predict and monitor QoE of voice service based on radio link parameters with low complexity for operators. Multiple Linear Regression (MLR) and Principal Component Analysis (PCA) are combined and used to establish the mapping model from radio link parameters to speech quality. Data set for model training and testing is obtained from real commercial network of China Mobile. The experimental results show that with sufficient training data, this algorithm can predict radio speech quality with high accuracy and could be used to monitor speech quality of mobile network in real time.展开更多
Unique ZnS nanobuns decorated with reduced graphene oxide (ROO) was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode (CE) in dye-sensitized solar cells (D...Unique ZnS nanobuns decorated with reduced graphene oxide (ROO) was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode (CE) in dye-sensitized solar cells (DSCs). Using this ZnS-ROO CE, a power conversion efficiency (PCE) of 7.03% was achieved. This value was 53% and 41 % higher than those of pure ZnS and ROO CEs, respectively. The ZnS-ROO nanocomposite is indeed an efficient and cost-effective Pt-like alternative for iodine reduction reaction.展开更多
BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical fac...BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical factors has synergistic effects on the recovery of peripheral nerve function. OBJECTIVE: To treat patients that received peripheral nerve entrapment surgery with comprehensive rehabilitation by decimeter wave therapy and electrical stimulation, and to observe the clinical effects of promoting nerve function recovery. DESIGN: Randomized controlled study. SETTINGS: Department of Orthopaedics, the Third Hospital of Baoding; Department of Hand Surgery, the Third Hospital of Hebei Medical University; Woman-Children Healthcare Center, Southern District, Baoding. PARTICIPANTS: A total of 124 patients, who received peripheral nerve entrapment surgery, were selected from the Department of Orthopaedics, the Third Hospital of Baoding between July 2001 and May 2007. All patients met the diagnostic standard of peripheral nerve entrapment syndrome defined by Doctor Chen in 1995. All subjects gave informed consent for treatments and conditions involved. The experiment was approved by a local ethics committee. All patients were randomly divided into four groups: electrical stimulation group, decimeter wave group, compound physical factor group, and control group, with 31 subjects in each group. METHODS: Patients received neurolysis at an appropriate interval after hospitalization. (1) Multi-form wave therapeutic equipment made in China was used to treat patients in the electrical stimulation group after neurolysis. Wave form, stimulus width, interval time, and stimulus intensity were regulated based on the grade of nerve injury. The details were as follows: mild nerve injury: 50-100-ms stimulus width and 1 500-2 000-ms intervals; moderate nerve injury: 100-200-ms stimulus width and 3 000-4 000-ms intervals; severe nerve injury: 200-300-ms stimulus width and 3 000--6 000-ms intervals. Current dosage was 20- 40 mA. The electrical stimulation was given 6 minutes/session, once a day, and 20 days were regarded as one treatment cycle. (2) A TMA-A double-frequent mild-hot therapeutic instrument was used on patients in the decimeter wave group after neurolysis. The therapeutic program was adapted to the early and middle-late phase. In the early phase, the decimeter wave was 10-15 W, 10 minutes/session, once a day; in the middle-late phase, the decimeter wave was 10-30 W, 20 minutes/session, once a day. Twenty days were regarded as one treatment cycle. (3) Patients in the compound physical factor group following neurolysis were treated the same as the decimeter wave group and electrical stimulation group, respectively. The treatment was performed once a day, and 20 days were regarded as one course. (4) Patients in the control group were not administered any physical treatment. MAIN OUTCOME MEASURES: Therapeutic efficacy was comprehensively evaluated based on motor and sensory evaluation criteria (set by Subassociation of Hand Surgery, Chinese Medical Association) at 1, 2, and 3 months after surgery, as well as changes in the electromyogram before and after operation. RESULTS: All 124 patients with peripheral nerve entrapment syndrome were included in the final analysis. One month after surgery, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were not significantly different from those in the control group (P 〉 0.05). There was also no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). Two months after surgery, fineness rates in the electrical stimulation group and decimeter wave group were not significantly different from the control group (P 〉 0.05). However, fineness rates were higher in the compound physical factor group compared to the other three groups (P 〈 0.05). There was no significant difference between the electrical stimulation group and the decimeter wave group (P 〉 0.05). Three months after operation, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were higher than the control group (P 〈 0.05). However, there was no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). CONCLUSION: The combination of decimeter wave therapy and electrical stimulation can remarkably shorten the recovery time of peripheral nerve function. The synergistic effect is superior to that of electrical stimulation and decimeter wave alone. This suggests that those two physical factors have synergistic effects on the treatment of peripheral nerve entrapment syndrome.展开更多
Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, ...Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.展开更多
Nanoscale materials are gaining massive attention in recent years due to their potential to alleviate the present electrochemical electrode constraints.Possessing high conductivity(both thermally and electrically),hig...Nanoscale materials are gaining massive attention in recent years due to their potential to alleviate the present electrochemical electrode constraints.Possessing high conductivity(both thermally and electrically),high chemical and electrochemical stability,exceptional mechanical strength and flexibility,high specific surface area,large charge storage capacity,and excellent ionadsorption,carbon nanotubes(CNTs)remain one of the most researched of other nanoscale materials for electrochemical energy storage.Rather than having them packed at random,CNTs perform better when packed/grown to order,vertically or horizontally aligned to a substrate.This study presents an overview of the impact of CNT alignment on the electrochemical performance of lithium-ion batteries(LIBs).The unique properties of vertically aligned CNTs(VACNTs)for LIB application were discussed.Furthermore,the mechanisms of charge storage and electrochemical performances in VACNT-based(pristine and composites)anodes and cathodes of LIBs were succinctly reviewed.In the end,the existing challenges and future directions in the field were also briefly discussed.展开更多
Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid cat...Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid catalyst for C-C bond formation via aldol condensation of furfural or HMF with acetone.The 4-(2-furyl)-3-buten-2-one and 1,5-di-2-furanyl-1,4-pentadien-3-one(FAc and F_(2)Ac),or 1,5-di-2-furanyl-1,4-pentadien-3-one and 1,5-bis[(5-hydroxlmethyl)-2-furanyl]-1,4-pentadien-3-one(HAc and H_(2)Ac),as two main condensation products of furfural with acetone or HMF with acetone,were observed.After 24 h at 160℃,86.9%conversion of furfural with 60.0%yield of the FAc as well as 7.5%yield of the F_(2)Ac and 88.9%conversion of the HMF with 41.1%yield of the HAc as well as 3.5%yield of the H_(2)Ac were achieved.Although furfural or HMF conversion was almost same after 24 h at 160℃,iron-modified MCM-41 zeolite catalyst displayed an enhanced selectivity to condensation products of furfural with acetone.In addition,catalysts showed an improved selectivity to the F_(2)Ac and H_(2)Ac at higher reaction temperature.The reusability and regeneration studies showed that iron-modified MCM-41 zeolite catalyst could not be reused directly,but could be regenerated by calcination in air,and the catalytic perfor-mance of regenerated catalyst was acceptable.展开更多
Pre-intercalation of metal ions into vanadium oxide is an effective strategy for optimizing the performance of rechargeable zinc-ion battery(ZIB)cathodes.However,the battery long-lifespan achievement and high-capacity...Pre-intercalation of metal ions into vanadium oxide is an effective strategy for optimizing the performance of rechargeable zinc-ion battery(ZIB)cathodes.However,the battery long-lifespan achievement and high-capacity retention remain a challenge.Increasing the electronic conductivity while simultaneously prompting the cathode diffusion kinetics can improve ZIB electrochemical performance.Herein,N-doped vanadium oxide(N-(Zn,en)VO)via defect engineering is reported as cathode for aqueous ZIBs.Positron annihilation and electron paramagnetic resonance clearly indicate oxygen vacancies in the material.Density functional theory(DFT)calculations show that N-doping and oxygen vacancies concurrently increase the electronic conductivity and accelerate the diffusion kinetics of zinc ions.Moreover,the presence of oxygen vacancies substantially increases the storage sites of zinc ions.Therefore,N-(Zn,en)VO exhibits excellent electrochemical performance,including a peak capacity of 420.5 mA h g^(-1)at 0.05 A g^(-1),a high power density of more than 10000 W kg^(-1)at 65.3 Wh kg^(-1),and a long cycle life at 5 A g^(-1)(4500 cycles without capacity decay).The methodology adopted in our study can be applied to other cathodic materials to improve their performance and extend their practical applications.展开更多
Faced with the challenge of high energy ablation problems, especially for laser ablation, effective energy dissipation protective materials fabricate by efficient preparation method is a feasible solution. The Ni-grap...Faced with the challenge of high energy ablation problems, especially for laser ablation, effective energy dissipation protective materials fabricate by efficient preparation method is a feasible solution. The Ni-graphite/Si O2 coatings with different Ni content were prepared by plasma spraying method with optimized plasma spraying parameters. All coatings are pure without oxidation and dense. Their ablation behaviors were investigated by high power continuous wave laser. The results indicate that the Ni-graphite/Si O2 coating with appropriate Ni content could realize the purpose of energy consumption by endothermal reaction of graphite/Si O2 and reflection improvement. High Ni content will block the occurrence of endothermal reaction of graphite/Si O2 and increase the heat diffusion to interior part of coating, which can make the ablation situation of coating more serious.展开更多
Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aur...Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB) is ubiquitously expressed while Aurora kinase C (AurkC) is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P) and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein (Oct4-paGFP) and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.展开更多
Single-pixel imaging is a burgeoning computational imaging technique that utilizes a single detector devoid of spatial resolution to capture an image,offering great potential for creating cost-effective and simplified...Single-pixel imaging is a burgeoning computational imaging technique that utilizes a single detector devoid of spatial resolution to capture an image,offering great potential for creating cost-effective and simplified imaging systems.Nevertheless,achieving super-resolution with a single pixel remains a formidable challenge.Here,we introduce a single-pixel super-resolution imaging technique based on space–time modulation.The modulation parametrically mixes the incoming signals,enabling the space–time scattered signals of the object carrying finer details to be captured by the single-pixel imaging system.To validate our proposed technique,we designed and fabricated a computational metasurface imager that needs only a single transmitting port and a single receiving port.The achieved resolution surpasses the Abbe resolution limit.The principle of our proposed technique is well-suited for low-cost and compact imaging systems.展开更多
基金Research Institute for Smart Energy(CDB2)the grant from the Research Institute for Advanced Manufacturing(CD8Z)+4 种基金the grant from the Carbon Neutrality Funding Scheme(WZ2R)at The Hong Kong Polytechnic Universitysupport from the Hong Kong Polytechnic University(CD9B,CDBZ and WZ4Q)the National Natural Science Foundation of China(22205187)Shenzhen Municipal Science and Technology Innovation Commission(JCYJ20230807140402006)Start-up Foundation for Introducing Talent of NUIST and Natural Science Foundation of Jiangsu Province of China(BK20230426).
文摘Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.
文摘Recently, Quality of Experience (QoE) of voice service has been paid more attentions because it represents the performance of voice service subjectively perceived by the end users. And speech quality is commonly used to measure the QoE value. In this paper, a speech quality assessment algorithm is proposed for GSM network, aiming to predict and monitor QoE of voice service based on radio link parameters with low complexity for operators. Multiple Linear Regression (MLR) and Principal Component Analysis (PCA) are combined and used to establish the mapping model from radio link parameters to speech quality. Data set for model training and testing is obtained from real commercial network of China Mobile. The experimental results show that with sufficient training data, this algorithm can predict radio speech quality with high accuracy and could be used to monitor speech quality of mobile network in real time.
基金supported by the National Natural Science Foundation of China(Grant No.51172102,51302125 and 51303076)
文摘Unique ZnS nanobuns decorated with reduced graphene oxide (ROO) was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode (CE) in dye-sensitized solar cells (DSCs). Using this ZnS-ROO CE, a power conversion efficiency (PCE) of 7.03% was achieved. This value was 53% and 41 % higher than those of pure ZnS and ROO CEs, respectively. The ZnS-ROO nanocomposite is indeed an efficient and cost-effective Pt-like alternative for iodine reduction reaction.
文摘BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical factors has synergistic effects on the recovery of peripheral nerve function. OBJECTIVE: To treat patients that received peripheral nerve entrapment surgery with comprehensive rehabilitation by decimeter wave therapy and electrical stimulation, and to observe the clinical effects of promoting nerve function recovery. DESIGN: Randomized controlled study. SETTINGS: Department of Orthopaedics, the Third Hospital of Baoding; Department of Hand Surgery, the Third Hospital of Hebei Medical University; Woman-Children Healthcare Center, Southern District, Baoding. PARTICIPANTS: A total of 124 patients, who received peripheral nerve entrapment surgery, were selected from the Department of Orthopaedics, the Third Hospital of Baoding between July 2001 and May 2007. All patients met the diagnostic standard of peripheral nerve entrapment syndrome defined by Doctor Chen in 1995. All subjects gave informed consent for treatments and conditions involved. The experiment was approved by a local ethics committee. All patients were randomly divided into four groups: electrical stimulation group, decimeter wave group, compound physical factor group, and control group, with 31 subjects in each group. METHODS: Patients received neurolysis at an appropriate interval after hospitalization. (1) Multi-form wave therapeutic equipment made in China was used to treat patients in the electrical stimulation group after neurolysis. Wave form, stimulus width, interval time, and stimulus intensity were regulated based on the grade of nerve injury. The details were as follows: mild nerve injury: 50-100-ms stimulus width and 1 500-2 000-ms intervals; moderate nerve injury: 100-200-ms stimulus width and 3 000-4 000-ms intervals; severe nerve injury: 200-300-ms stimulus width and 3 000--6 000-ms intervals. Current dosage was 20- 40 mA. The electrical stimulation was given 6 minutes/session, once a day, and 20 days were regarded as one treatment cycle. (2) A TMA-A double-frequent mild-hot therapeutic instrument was used on patients in the decimeter wave group after neurolysis. The therapeutic program was adapted to the early and middle-late phase. In the early phase, the decimeter wave was 10-15 W, 10 minutes/session, once a day; in the middle-late phase, the decimeter wave was 10-30 W, 20 minutes/session, once a day. Twenty days were regarded as one treatment cycle. (3) Patients in the compound physical factor group following neurolysis were treated the same as the decimeter wave group and electrical stimulation group, respectively. The treatment was performed once a day, and 20 days were regarded as one course. (4) Patients in the control group were not administered any physical treatment. MAIN OUTCOME MEASURES: Therapeutic efficacy was comprehensively evaluated based on motor and sensory evaluation criteria (set by Subassociation of Hand Surgery, Chinese Medical Association) at 1, 2, and 3 months after surgery, as well as changes in the electromyogram before and after operation. RESULTS: All 124 patients with peripheral nerve entrapment syndrome were included in the final analysis. One month after surgery, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were not significantly different from those in the control group (P 〉 0.05). There was also no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). Two months after surgery, fineness rates in the electrical stimulation group and decimeter wave group were not significantly different from the control group (P 〉 0.05). However, fineness rates were higher in the compound physical factor group compared to the other three groups (P 〈 0.05). There was no significant difference between the electrical stimulation group and the decimeter wave group (P 〉 0.05). Three months after operation, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were higher than the control group (P 〈 0.05). However, there was no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). CONCLUSION: The combination of decimeter wave therapy and electrical stimulation can remarkably shorten the recovery time of peripheral nerve function. The synergistic effect is superior to that of electrical stimulation and decimeter wave alone. This suggests that those two physical factors have synergistic effects on the treatment of peripheral nerve entrapment syndrome.
基金supported by the National Natural Science Foundation of China(21325208,21172209,21272050,21402181,21572212)Chinese Academy of Science(KJCX2-EW-J02,YZ201563)+5 种基金the Major/Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology(2014FXCX006)China Postdoctoral Science Foundation(2014M561835)the Specialized Research Fund for the Doctoral Program of Higher Education(20123402130008)Fundamental Research Funds for the Central Universities(WK2060190025,WK2060190033,WK2060190040,WK6030000023)the Key Technologies R&D Programme of Anhui Province(1604a0702027)Program for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of China
文摘Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.
基金supported by the National Science Foundation of the United States(Nos.1506640,2134375,and 2213923).
文摘Nanoscale materials are gaining massive attention in recent years due to their potential to alleviate the present electrochemical electrode constraints.Possessing high conductivity(both thermally and electrically),high chemical and electrochemical stability,exceptional mechanical strength and flexibility,high specific surface area,large charge storage capacity,and excellent ionadsorption,carbon nanotubes(CNTs)remain one of the most researched of other nanoscale materials for electrochemical energy storage.Rather than having them packed at random,CNTs perform better when packed/grown to order,vertically or horizontally aligned to a substrate.This study presents an overview of the impact of CNT alignment on the electrochemical performance of lithium-ion batteries(LIBs).The unique properties of vertically aligned CNTs(VACNTs)for LIB application were discussed.Furthermore,the mechanisms of charge storage and electrochemical performances in VACNT-based(pristine and composites)anodes and cathodes of LIBs were succinctly reviewed.In the end,the existing challenges and future directions in the field were also briefly discussed.
基金supported by National Key R&D Program of China(No.2018YFB1501601)National Natural Science Foundation of China(No.51676178)Transformational Technologies for Clean Energy and Demonstration,and Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21060101).
文摘Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid catalyst for C-C bond formation via aldol condensation of furfural or HMF with acetone.The 4-(2-furyl)-3-buten-2-one and 1,5-di-2-furanyl-1,4-pentadien-3-one(FAc and F_(2)Ac),or 1,5-di-2-furanyl-1,4-pentadien-3-one and 1,5-bis[(5-hydroxlmethyl)-2-furanyl]-1,4-pentadien-3-one(HAc and H_(2)Ac),as two main condensation products of furfural with acetone or HMF with acetone,were observed.After 24 h at 160℃,86.9%conversion of furfural with 60.0%yield of the FAc as well as 7.5%yield of the F_(2)Ac and 88.9%conversion of the HMF with 41.1%yield of the HAc as well as 3.5%yield of the H_(2)Ac were achieved.Although furfural or HMF conversion was almost same after 24 h at 160℃,iron-modified MCM-41 zeolite catalyst displayed an enhanced selectivity to condensation products of furfural with acetone.In addition,catalysts showed an improved selectivity to the F_(2)Ac and H_(2)Ac at higher reaction temperature.The reusability and regeneration studies showed that iron-modified MCM-41 zeolite catalyst could not be reused directly,but could be regenerated by calcination in air,and the catalytic perfor-mance of regenerated catalyst was acceptable.
基金National Natural Science Foundation of China,Grant/Award Numbers:51732007,51902187,52072224Natural Science Foundation of Shandong Province,Grant/Award Numbers:ZR2018BEM010,ZR2020YQ35+1 种基金Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongYoung Elite Scientists Sponsorship Program,Grant/Award Number:2019QNRC001。
文摘Pre-intercalation of metal ions into vanadium oxide is an effective strategy for optimizing the performance of rechargeable zinc-ion battery(ZIB)cathodes.However,the battery long-lifespan achievement and high-capacity retention remain a challenge.Increasing the electronic conductivity while simultaneously prompting the cathode diffusion kinetics can improve ZIB electrochemical performance.Herein,N-doped vanadium oxide(N-(Zn,en)VO)via defect engineering is reported as cathode for aqueous ZIBs.Positron annihilation and electron paramagnetic resonance clearly indicate oxygen vacancies in the material.Density functional theory(DFT)calculations show that N-doping and oxygen vacancies concurrently increase the electronic conductivity and accelerate the diffusion kinetics of zinc ions.Moreover,the presence of oxygen vacancies substantially increases the storage sites of zinc ions.Therefore,N-(Zn,en)VO exhibits excellent electrochemical performance,including a peak capacity of 420.5 mA h g^(-1)at 0.05 A g^(-1),a high power density of more than 10000 W kg^(-1)at 65.3 Wh kg^(-1),and a long cycle life at 5 A g^(-1)(4500 cycles without capacity decay).The methodology adopted in our study can be applied to other cathodic materials to improve their performance and extend their practical applications.
基金financially supported by the National Natural Science Foundation of China(No.51302013)。
文摘Faced with the challenge of high energy ablation problems, especially for laser ablation, effective energy dissipation protective materials fabricate by efficient preparation method is a feasible solution. The Ni-graphite/Si O2 coatings with different Ni content were prepared by plasma spraying method with optimized plasma spraying parameters. All coatings are pure without oxidation and dense. Their ablation behaviors were investigated by high power continuous wave laser. The results indicate that the Ni-graphite/Si O2 coating with appropriate Ni content could realize the purpose of energy consumption by endothermal reaction of graphite/Si O2 and reflection improvement. High Ni content will block the occurrence of endothermal reaction of graphite/Si O2 and increase the heat diffusion to interior part of coating, which can make the ablation situation of coating more serious.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grant No. 31171381), NSFC-MRC China-UK collaborative project grant 81261130320, the Beijing Natural Science Foundation grant 20151100084 (J.N.), the National Basic Research Program (973 Program) (Nos. 2016YFC0900301 and 2015CB856201 ), the Youth Thousand Scholar Program of China (W.X.), and the funding from the Tsinghua-Peking Center for Life Sciences (W.X., J.N.). We thank the animal facility, SLSTH-Nikon Biological Imaging Center of Tsinghua University for assistance with fluorescence imaging and Dr. Richard de Grijs for helpful comments and English language editing of the manuscript. All authors have contributed to, read, and approved the manuscript for submission.
文摘Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB) is ubiquitously expressed while Aurora kinase C (AurkC) is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P) and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein (Oct4-paGFP) and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.
基金National Natural Science Foundation of China(61731007,62071152,62271170)。
文摘Single-pixel imaging is a burgeoning computational imaging technique that utilizes a single detector devoid of spatial resolution to capture an image,offering great potential for creating cost-effective and simplified imaging systems.Nevertheless,achieving super-resolution with a single pixel remains a formidable challenge.Here,we introduce a single-pixel super-resolution imaging technique based on space–time modulation.The modulation parametrically mixes the incoming signals,enabling the space–time scattered signals of the object carrying finer details to be captured by the single-pixel imaging system.To validate our proposed technique,we designed and fabricated a computational metasurface imager that needs only a single transmitting port and a single receiving port.The achieved resolution surpasses the Abbe resolution limit.The principle of our proposed technique is well-suited for low-cost and compact imaging systems.