Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low tem...Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low temperatures,increase fuel conversion and the heat sink capacity,and suppress coke deposition,thereby reducing waste heat.Catalysts mainly include metal oxide catalysts,noble metal catalysts and metal nanoparticles,zeolite catalysts,nanozeolite catalysts,and coating catalysts.Moreover,initiators roughly include nitrogenous compounds,oxygenated compounds,and hyperbranched polymer initiators.In this review,we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking.This review will facilitate the development of the synthesis and exploration of catalysts and initiators.展开更多
[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and t...[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and that of GGE at 148.7℃. However, CFA had much less thermal initiating activity under 300℃. Under UV radiation for short time, the thermal initiating activities of CFN and CFA were enhanced obviously. It was observed that the initiating onset temperature decreased and the evolved heat of the curing increased. Both CFN and CFA can carry out the polymerization of E44 and GGE near 85℃ and 112℃ by UV radiation.展开更多
In this paper, three different kinds of β-CD derivatives were synthesized as atom transfer radical polymerization（ATRP） initiator or reversible addition-fragmentation chain transfer polymerization（RAFT） chain tra...In this paper, three different kinds of β-CD derivatives were synthesized as atom transfer radical polymerization（ATRP） initiator or reversible addition-fragmentation chain transfer polymerization（RAFT） chain transfers. The degree of substitution for each derivative was carefully characterized through 1H-NMR, 13C-NMR spectroscopy and matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF-MS）. The factors influencing the degree of substitution were discussed. Moreover, the comparison between ATRP and RAFT was shown in the polymerization of Nisopropyl acrylamide（NIPAM）.展开更多
It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA a...It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA and PMA with controlled molecular weight and low polydispersity were obtained by using non-acetal initiators in the presence of bibenzoate,bifluo ide or Hgl_2,The living nature of polymerization is shown by the correspondence of theoretical and observed molecular weight and the preparation of A-B-A type triblock copolymer with methacrylate and acrylate segments can be prepared.展开更多
A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kine...A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kinetic equation is also studied.展开更多
Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ig...Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.展开更多
The solubility of initiator determines its distribution and the roles played in emulsion polymerization as well as the final products, but this is still lack of systematic investigation. The present work focuses on th...The solubility of initiator determines its distribution and the roles played in emulsion polymerization as well as the final products, but this is still lack of systematic investigation. The present work focuses on this issue by comparing the kinetic behaviors and product properties of styrene emulsion polymerization initiated by 2,2-azoisobutyronitrile(AIBN) and potassium persulphate(KPS).Compared to KPS-initiated emulsion polymerization, the AIBN-initiated polymerization was found to be insensitive to the type of emulsifier, and have high polymerization rate as well as narrow molecular weight distribution and particle size distribution. This result indicates the effective free radicals are generated in micelles or colloids, which could decrease the proportion of homogeneous nucleation and make the process and product more controllable. As a consequence, there is a linear relationship between molecular weight of product and AIBN concentration in lg-lg coordinate. It provided a reference for the preparation of latexes with specified molecular weight and supported the possibility of the coexistence of multiple free radicals in one micelle or colloid when using oil-soluble initiator.展开更多
Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce p...Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.展开更多
In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional gro...In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 （V- 601, dimethyl 2,2＇-azobis（isobutyrate））, --CN （V-65, 2,2＇-Azobis（2,4-diemthylvaleronitrile））, --COOH （V-501, 4,4＇-azobis（4-cyanovaleric acid）） and --NH-（VA-061, 2,2＇-azobis[2-（2-imidazolin-2-yl）propane]）, respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy （SEM） and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.展开更多
The anionic polymerization of N-vinylcarbazole（NVC） by using optically active anionic initiators such as the lithium salts of（S）-1-（9H-fluoren-2-yl）-4-isopropyl-4,5-dihydrooxazole（（S）-1-FIDH） and（S）-2-（9H...The anionic polymerization of N-vinylcarbazole（NVC） by using optically active anionic initiators such as the lithium salts of（S）-1-（9H-fluoren-2-yl）-4-isopropyl-4,5-dihydrooxazole（（S）-1-FIDH） and（S）-2-（9H-fluoren-2-yl）-4-isopropyl-4,5-dihydrooxazole（（S）-2-FIDH） and complexes of（-）-Sparteine with n-butylithium（n-Bu Li-（-）-Sp） or fluorenyl lithium（FILi-（-）-Sp） was achieved. The yield and specific rotation of poly（N-vinylcarbazole）s（poly（NVC）s） were considerably affected by the molar ratio of（S）-FIDH to NVC. The highest yield and specific rotation were obtained with Li-（S）-1-FIDH as an initiator, with a molar ratio of monomer and initiator [M]/[I] = 10/1. The effects of the chiral initiators, type of solvent and the polymerization temperature were investigated. The obtained optical activity of polymers was attributed to asymmetric induction of the chiral initiators.展开更多
Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with u...Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with uniform rate at different temperatures at which various grades of poly(vinyl chloride) will be prepared.展开更多
Batch cationic emulsion polymerization was carried out with styrene(St)and butyl acrylate(BA)as non-ionic monomer,Cetyl trimethyl ammonium chloride(CTAC)as emulsifier,and Azobis isobutyl amidine hydrochloride(AIBA)or ...Batch cationic emulsion polymerization was carried out with styrene(St)and butyl acrylate(BA)as non-ionic monomer,Cetyl trimethyl ammonium chloride(CTAC)as emulsifier,and Azobis isobutyl amidine hydrochloride(AIBA)or Azo diisopropyl imidazoline hydrochloride(AIBI)as initiator.The effects of amount and molecule structure of initiators on latex particle size,PDI and particle morphology were analyzed.Results showed that higher initiator amount resulted in smaller particle size and higher PDI.Besides,smaller particle size were obtained when AIBI was used as initiator.展开更多
Nature|大型汉族人群队列助力中国台湾精准医疗精准医学的发展依赖于大规模、具有深度表型和基因变异图谱数据的人群队列,然而这在非欧洲人群中数据仍严重不足。中国台湾精准医学计划(Taiwan Precision Medicine Initiative,TPMI)旨在...Nature|大型汉族人群队列助力中国台湾精准医疗精准医学的发展依赖于大规模、具有深度表型和基因变异图谱数据的人群队列,然而这在非欧洲人群中数据仍严重不足。中国台湾精准医学计划(Taiwan Precision Medicine Initiative,TPMI)旨在建立一个具有广泛代表性的中国台湾汉族人群队列,以支持大规模基因组与健康医学研究(2025年10月15日在线发表,doi:10.1038/s41586-025-09680-x)。展开更多
Stanbic Bank Zimbabwe is strategically positioning itself as a critical bridge for Zimbabwe’s local businesses,seeking to navigate the vast and complex Chinese market.
As we enter the year 2026,the international system continues to receive shocks from Donald Trump,arguably the 21st century’s most disruptive US leader.His return to the White House in 2025 coincided with the 80th ann...As we enter the year 2026,the international system continues to receive shocks from Donald Trump,arguably the 21st century’s most disruptive US leader.His return to the White House in 2025 coincided with the 80th anniversary of the defeat of fascism and the establishment of the United Nations,the multilateral platform that carried the world’s hope for peace,restraint and collective security.The coincidence was unsettling.A world order designed to limit power now confronts a moment in which power is exercised openly,transactionally and unapologetically.展开更多
Amyloid-β(Aβ)and tau,the two hallmark proteins associated with Alzheimer’s disease(AD),exhibit distinct toxic effects but also interact synergistically within the disease pathology.The prevailing theory in AD patho...Amyloid-β(Aβ)and tau,the two hallmark proteins associated with Alzheimer’s disease(AD),exhibit distinct toxic effects but also interact synergistically within the disease pathology.The prevailing theory in AD pathology-the amyloid cascade hypothesis-highlights the pivotal role of increased processing of the amyloid precursor protein(APP).Initially cleaved by the majorβ-secretase(β-amyloid cleaving enzyme-1,BACE1)in the brain,then undergoes further cleavage by theγ-secretase complex,resulting in the production of Aβ_(40-42)and a set of intracellular C-terminal peptides known as Aβand APP intracellular domain(β-AICDs)and soluble amyloid precursor proteinβ(sAPPβ)(Orobets and Karamyshev,2023).展开更多
The NSC-34 cell line is a widely recognized motor neuron model and various neuronal differentiation protocols have been exploited. Under previously reported experimental conditions, only part of the cells resemble dif...The NSC-34 cell line is a widely recognized motor neuron model and various neuronal differentiation protocols have been exploited. Under previously reported experimental conditions, only part of the cells resemble differentiated neurons;however, they do not exhibit extensive and time-prolonged neuritogenesis, and maintain their duplication capacity in culture. The aim of the present work was to facilitate long-term and more homogeneous neuronal differentiation in motor neuron–like NSC-34 cells. We found that the antimitotic drug cytosine arabinoside promoted robust and persistent neuronal differentiation in the entire cell population. Long and interconnecting neuronal processes with abundant growth cones were homogeneously induced and were durable for up to at least 6 weeks in culture. Moreover, cytosine arabinoside was permissive, dispensable, and mostly irreversible in priming NSC-34 cells for neurite initiation and regeneration after mechanical dislodgement. Finally, the expression of the cell proliferation antigen Ki67 was inhibited by cytosine arabinoside, whereas the expression levels of neuronal growth associated protein 43, vimentin, and motor neuron–specific p75, Islet2, homeobox 9 markers were upregulated, as confirmed by western blot and/or confocal immunofluorescence analysis. Overall, these findings support the use of NSC-34 cells as a motor neuron model for properly investigating neurodegenerative mechanisms and prospectively identifying neuroprotective strategies.展开更多
To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,insp...To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.展开更多
Stem cell fate decisions are increasingly understood through the dynamic interplay of two fundamental stress-adaptive programs:the integrated stress response(ISR)and the senescence-associated secretory phenotype(SASP)...Stem cell fate decisions are increasingly understood through the dynamic interplay of two fundamental stress-adaptive programs:the integrated stress response(ISR)and the senescence-associated secretory phenotype(SASP).These pathways act as a Yin-Yang system,balancing beneficial and detrimental outcomes across development,tissue homeostasis,and disease.On the yin(protective)side,transient ISR activation and acute SASP signaling foster adaptation,embryonic patterning,wound healing,and regeneration.On the yang(maladaptive)side,chronic ISR signaling and unresolved SASP output drive stem cell exhaustion,fibrosis,inflammation,and tumorigenesis.This duality highlights their roles as both guardians and disruptors of stem cell integrity.Mechanistically,ISR regulates translational control via eukaryotic initiation factor 2 alpha(eIF2α)phosphorylation and activating transcription factor 4(ATF4)-dependent transcription,while SASP reprograms the extracellular milieu through cytokines,growth factors,and proteases.Their crosstalk creates feedback loops that shape tissue niches and long-termstemcell potential.Framing ISR-SASP interactions through a Yin-Yang lens underscores the balance between resilience and decline,to offer new insights into regenerative medicine,anti-aging interventions,and cancer therapeutics.展开更多
China Standardization:What is your view on this year's International Standardization Youth Star Competition?Tom Heilandt:This is the first time I have attended this event,which was founded by my good friend Dr.Zha...China Standardization:What is your view on this year's International Standardization Youth Star Competition?Tom Heilandt:This is the first time I have attended this event,which was founded by my good friend Dr.Zhang Xiaogang,whom I first met in 2016 when he was President of ISO.It is an excellent initiative.I strongly believe that it is essential for young people to become involved in standardization.展开更多
基金supported by the National Natural Science Foundation of China(No.21978200).
文摘Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low temperatures,increase fuel conversion and the heat sink capacity,and suppress coke deposition,thereby reducing waste heat.Catalysts mainly include metal oxide catalysts,noble metal catalysts and metal nanoparticles,zeolite catalysts,nanozeolite catalysts,and coating catalysts.Moreover,initiators roughly include nitrogenous compounds,oxygenated compounds,and hyperbranched polymer initiators.In this review,we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking.This review will facilitate the development of the synthesis and exploration of catalysts and initiators.
文摘[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and that of GGE at 148.7℃. However, CFA had much less thermal initiating activity under 300℃. Under UV radiation for short time, the thermal initiating activities of CFN and CFA were enhanced obviously. It was observed that the initiating onset temperature decreased and the evolved heat of the curing increased. Both CFN and CFA can carry out the polymerization of E44 and GGE near 85℃ and 112℃ by UV radiation.
基金financially supported by the National Natural Science Foundation of China(Nos.21174076 and 21374053)
文摘In this paper, three different kinds of β-CD derivatives were synthesized as atom transfer radical polymerization（ATRP） initiator or reversible addition-fragmentation chain transfer polymerization（RAFT） chain transfers. The degree of substitution for each derivative was carefully characterized through 1H-NMR, 13C-NMR spectroscopy and matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF-MS）. The factors influencing the degree of substitution were discussed. Moreover, the comparison between ATRP and RAFT was shown in the polymerization of Nisopropyl acrylamide（NIPAM）.
文摘It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA and PMA with controlled molecular weight and low polydispersity were obtained by using non-acetal initiators in the presence of bibenzoate,bifluo ide or Hgl_2,The living nature of polymerization is shown by the correspondence of theoretical and observed molecular weight and the preparation of A-B-A type triblock copolymer with methacrylate and acrylate segments can be prepared.
文摘A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kinetic equation is also studied.
文摘Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.
基金the financial support of the National Natural Science Foundation of China(Nos.21422603 and U1662120)
文摘The solubility of initiator determines its distribution and the roles played in emulsion polymerization as well as the final products, but this is still lack of systematic investigation. The present work focuses on this issue by comparing the kinetic behaviors and product properties of styrene emulsion polymerization initiated by 2,2-azoisobutyronitrile(AIBN) and potassium persulphate(KPS).Compared to KPS-initiated emulsion polymerization, the AIBN-initiated polymerization was found to be insensitive to the type of emulsifier, and have high polymerization rate as well as narrow molecular weight distribution and particle size distribution. This result indicates the effective free radicals are generated in micelles or colloids, which could decrease the proportion of homogeneous nucleation and make the process and product more controllable. As a consequence, there is a linear relationship between molecular weight of product and AIBN concentration in lg-lg coordinate. It provided a reference for the preparation of latexes with specified molecular weight and supported the possibility of the coexistence of multiple free radicals in one micelle or colloid when using oil-soluble initiator.
基金the Science and Technology on Applied Physical Chemistry Laboratory, China (Grant No.6142602220101) to provide fund for conducting experiments。
文摘Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.
基金financially supported by the National Natural Science Foundation of China(No.51073035)
文摘In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 （V- 601, dimethyl 2,2＇-azobis（isobutyrate））, --CN （V-65, 2,2＇-Azobis（2,4-diemthylvaleronitrile））, --COOH （V-501, 4,4＇-azobis（4-cyanovaleric acid）） and --NH-（VA-061, 2,2＇-azobis[2-（2-imidazolin-2-yl）propane]）, respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy （SEM） and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.
基金financially supported by the open project program of Key Laboratory of Environmentally Friendly ChemistryApplications of the Ministry of Education,China(No.09HJYH04)Xiangtan University Doctoral Scientific Research Fund
文摘The anionic polymerization of N-vinylcarbazole（NVC） by using optically active anionic initiators such as the lithium salts of（S）-1-（9H-fluoren-2-yl）-4-isopropyl-4,5-dihydrooxazole（（S）-1-FIDH） and（S）-2-（9H-fluoren-2-yl）-4-isopropyl-4,5-dihydrooxazole（（S）-2-FIDH） and complexes of（-）-Sparteine with n-butylithium（n-Bu Li-（-）-Sp） or fluorenyl lithium（FILi-（-）-Sp） was achieved. The yield and specific rotation of poly（N-vinylcarbazole）s（poly（NVC）s） were considerably affected by the molar ratio of（S）-FIDH to NVC. The highest yield and specific rotation were obtained with Li-（S）-1-FIDH as an initiator, with a molar ratio of monomer and initiator [M]/[I] = 10/1. The effects of the chiral initiators, type of solvent and the polymerization temperature were investigated. The obtained optical activity of polymers was attributed to asymmetric induction of the chiral initiators.
文摘Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with uniform rate at different temperatures at which various grades of poly(vinyl chloride) will be prepared.
基金supported by National Natural Science Foundation of China,Grant No.51173086National Key Technology R&D Program,Grant No.2014BAC13B02 and 2014BAE01B01Industrialization Projects of Major Independent Innovation Achievements of Shandong Province,Grant No.2012ZHZX1A0914
文摘Batch cationic emulsion polymerization was carried out with styrene(St)and butyl acrylate(BA)as non-ionic monomer,Cetyl trimethyl ammonium chloride(CTAC)as emulsifier,and Azobis isobutyl amidine hydrochloride(AIBA)or Azo diisopropyl imidazoline hydrochloride(AIBI)as initiator.The effects of amount and molecule structure of initiators on latex particle size,PDI and particle morphology were analyzed.Results showed that higher initiator amount resulted in smaller particle size and higher PDI.Besides,smaller particle size were obtained when AIBI was used as initiator.
文摘Nature|大型汉族人群队列助力中国台湾精准医疗精准医学的发展依赖于大规模、具有深度表型和基因变异图谱数据的人群队列,然而这在非欧洲人群中数据仍严重不足。中国台湾精准医学计划(Taiwan Precision Medicine Initiative,TPMI)旨在建立一个具有广泛代表性的中国台湾汉族人群队列,以支持大规模基因组与健康医学研究(2025年10月15日在线发表,doi:10.1038/s41586-025-09680-x)。
文摘Stanbic Bank Zimbabwe is strategically positioning itself as a critical bridge for Zimbabwe’s local businesses,seeking to navigate the vast and complex Chinese market.
文摘As we enter the year 2026,the international system continues to receive shocks from Donald Trump,arguably the 21st century’s most disruptive US leader.His return to the White House in 2025 coincided with the 80th anniversary of the defeat of fascism and the establishment of the United Nations,the multilateral platform that carried the world’s hope for peace,restraint and collective security.The coincidence was unsettling.A world order designed to limit power now confronts a moment in which power is exercised openly,transactionally and unapologetically.
文摘Amyloid-β(Aβ)and tau,the two hallmark proteins associated with Alzheimer’s disease(AD),exhibit distinct toxic effects but also interact synergistically within the disease pathology.The prevailing theory in AD pathology-the amyloid cascade hypothesis-highlights the pivotal role of increased processing of the amyloid precursor protein(APP).Initially cleaved by the majorβ-secretase(β-amyloid cleaving enzyme-1,BACE1)in the brain,then undergoes further cleavage by theγ-secretase complex,resulting in the production of Aβ_(40-42)and a set of intracellular C-terminal peptides known as Aβand APP intracellular domain(β-AICDs)and soluble amyloid precursor proteinβ(sAPPβ)(Orobets and Karamyshev,2023).
基金supported by FATALSDrug Project [Progetti di Ricerca@CNR SAC.AD002.173.058] from National Research Council,Italy (to CV)。
文摘The NSC-34 cell line is a widely recognized motor neuron model and various neuronal differentiation protocols have been exploited. Under previously reported experimental conditions, only part of the cells resemble differentiated neurons;however, they do not exhibit extensive and time-prolonged neuritogenesis, and maintain their duplication capacity in culture. The aim of the present work was to facilitate long-term and more homogeneous neuronal differentiation in motor neuron–like NSC-34 cells. We found that the antimitotic drug cytosine arabinoside promoted robust and persistent neuronal differentiation in the entire cell population. Long and interconnecting neuronal processes with abundant growth cones were homogeneously induced and were durable for up to at least 6 weeks in culture. Moreover, cytosine arabinoside was permissive, dispensable, and mostly irreversible in priming NSC-34 cells for neurite initiation and regeneration after mechanical dislodgement. Finally, the expression of the cell proliferation antigen Ki67 was inhibited by cytosine arabinoside, whereas the expression levels of neuronal growth associated protein 43, vimentin, and motor neuron–specific p75, Islet2, homeobox 9 markers were upregulated, as confirmed by western blot and/or confocal immunofluorescence analysis. Overall, these findings support the use of NSC-34 cells as a motor neuron model for properly investigating neurodegenerative mechanisms and prospectively identifying neuroprotective strategies.
基金National Natural Science Foundation of China under Grant Nos.52478488 and 51908013the National Key Basic Research and Development Program of China under Grant No.2018YFC1504305。
文摘To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.
基金funded by the National Institutes of Health,grant numbers UG3OD023285,P42ES030991,and P30ES036084.
文摘Stem cell fate decisions are increasingly understood through the dynamic interplay of two fundamental stress-adaptive programs:the integrated stress response(ISR)and the senescence-associated secretory phenotype(SASP).These pathways act as a Yin-Yang system,balancing beneficial and detrimental outcomes across development,tissue homeostasis,and disease.On the yin(protective)side,transient ISR activation and acute SASP signaling foster adaptation,embryonic patterning,wound healing,and regeneration.On the yang(maladaptive)side,chronic ISR signaling and unresolved SASP output drive stem cell exhaustion,fibrosis,inflammation,and tumorigenesis.This duality highlights their roles as both guardians and disruptors of stem cell integrity.Mechanistically,ISR regulates translational control via eukaryotic initiation factor 2 alpha(eIF2α)phosphorylation and activating transcription factor 4(ATF4)-dependent transcription,while SASP reprograms the extracellular milieu through cytokines,growth factors,and proteases.Their crosstalk creates feedback loops that shape tissue niches and long-termstemcell potential.Framing ISR-SASP interactions through a Yin-Yang lens underscores the balance between resilience and decline,to offer new insights into regenerative medicine,anti-aging interventions,and cancer therapeutics.
文摘China Standardization:What is your view on this year's International Standardization Youth Star Competition?Tom Heilandt:This is the first time I have attended this event,which was founded by my good friend Dr.Zhang Xiaogang,whom I first met in 2016 when he was President of ISO.It is an excellent initiative.I strongly believe that it is essential for young people to become involved in standardization.
