To realize the commercialize of rechargeable Zn-air battery(RZAB),developing metal-free bifunctional electrocatalysts with satisfactory activity for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is o...To realize the commercialize of rechargeable Zn-air battery(RZAB),developing metal-free bifunctional electrocatalysts with satisfactory activity for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is one of the emerging issues.Herein,a prawn shells-derived N-enriched porous carbon(PSNC)is synthesized via an ion exchange coupled biomimetic selfsacrificing template strategy.The resulting PSNC displays unique functional components,including the interconnected macro-meso-micropores structure to shorten charge and mass transfer pathway,high content of pyridinic and graphitic nitrogen to construct rich catalytic active site and improve conductivity.As electrocatalysts in alkaline condition,the optimized PSNC-0.8 achieves excellent bifunctional catalytic propriety with a narrow potential gap(ΔE)value of 0.80 V.Meanwhile,PSNC-0.8-based RZAB displays a high peak power density of 176.5 mW·cm^(-2)and considerable cycling durability with a small battery efficiency delay of 6.5%after 480 cycles(320 h).This study enlightens a simple and effective conception to design high-performance metal-free bifunctional electrocatalysts from seafood waste.展开更多
Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)prec...Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)precursors in different rock types remains poorly understood.This study investigates the AE characteristics and early warning times of rockburst in slate and mica-schist under four LRs(0.05,0.15,0.25,and 0.5 MPa/s)using true triaxial unloading tests.The micro-crack state of the samples was evaluated using entropy,while critical slowing down(CSD)theory was applied to interpret AE precursors.The results reveal that as the LR increases,the rockburst stress of both rocks initially rises and then declines,with mica-schist exhibiting more severe damage and a higher dominance of tensile cracks.Notably,identifying rockburst precursors in mica-schist proved more challenging compared to slate.Among the methods tested,AE amplitude variance outperformed entropy in precursor identification.Additionally,the rockburst early warning time was found to be negatively correlated with the LR,with mica-schist consistently showing shorter warning times than slate.The CSD-derived precursor,due to its enhanced sensitivity,is recommended for early warning systems.These findings provide new insights into the role of LRs in rockburst dynamics and offer practical guidance for improving precursor identification and disaster mitigation strategies.展开更多
Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechani...Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.展开更多
The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detect...The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detection systems often struggle with detecting early-stage threats,particularly in dynamic environments such as IoT,SDNs,and cloud infrastructures.These systems are hindered by high false positive rates,poor adaptability to evolving threats,and reliance on large labeled datasets.To address these challenges,this paper introduces CyberGuard-X,an AI-driven framework designed to identify attack precursors—subtle indicators of malicious intent—before full-scale intrusions occur.CyberGuard-X integrates anomaly detection,time-series analysis,and multi-stage classification within a scalable architecture.The model leverages deep learning techniques such as autoencoders,LSTM networks,and Transformer layers,supported by semi-supervised learning to enhance detection of zero-day and rare threats.Extensive experiments on benchmark datasets(CICIDS2017,CSE-CIC-IDS2018,and UNSW-NB15)demonstrate strong results,including 96.1%accuracy,94.7%precision,and 95.3%recall,while achieving a zero-day detection rate of 84.5%.With an inference time of 12.8 ms and 34.5%latency reduction,the model supports real-time deployment in resource-constrained environments.CyberGuard-X not only surpasses baseline models like LSTM and Random Forest but also enhances proactive threat mitigation across diverse network settings.展开更多
This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic ...This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic response mechanism of coal energy evolution is examined, and the energy instability criterion is established. The validity of the instability criterion is explored from the standpoint of damage progression. The results demonstrate that the energy conversion mechanism undergoes a fundamental alternation under impact disturbance. Moreover, the energy release rate as well as the energy dissipation rate undergo comparable changes across distinct levels of impact disturbance. The distinction between the energy release rate and the energy dissipation rate (DRD) increases as coal mass deformation grows. Prior to coal facing instability and failure, the DRD experienced an inflection point followed by a sharp decrease. In conjunction with the discussion on the damage evolution, the physical and mechanical significance of DRD remains clear, which can essentially describe the whole impact loading process. The phenomenon that the inflection point appears and DRD subsequently suddenly decreases can be employed as the energy criterion prior to the failure of instability. Furthermore, this paper provides significant reference for the prediction of dynamic instability of coal under dynamic disturbance.展开更多
The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which ha...The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which hampers their conversion into boride-based ultrahigh temperature ceramics.To tackle these challenges,a serious of pioneering liquid multi-component hafnium-containing ceramic SiHfCB precursors(with different Hf/Si ratios)have been developed.These novel precursors are featured with stable molec-ular structure and high ceramic yield which were successfully created through a novel one-pot polymer-ization process.They present in liquid form and their structure is characterized by C-C bonds forming its main chain with branched chains of O-Si-O,Si-O-Hf,Si-O-B,and B-O-Hf which have untapped advantages including uniform component dispersion,and excellent fluidity.The ceramic yield of SiHfCB precursor with Hf/Si of 0.2 is remarkably up to 68.6 wt.%at 1500℃,and their Hf content exceeded 50 wt.%.Of particular interest,the pyrolyzed product HfB_(2)-SiC nanopowders derived from the SiHfCB precursor with Hf/Si of 0.2,consist of nanopowders in the 40-60 nm range with a density of 5.23 g cm^(−3).Remarkably,this material demonstrates exceptional performance in ultrahigh temperature oxygen-containing environ-ments at 2500℃,showing near-zero ablation with a linear ablation rate of just 2.5×10^(−4) mm s^(−1).Post-ablation analysis of the microstructure reveals that the formation of a lava-like HfO_(2) and HfO_(2)-SiO_(2) oxide layer effectively blocks oxygen penetration and provides excellent oxidation resistance.The inno-vative SiHfCB hafnium-containing ceramic precursor offers a groundbreaking solution for the preparation of lightweight ultrahigh-temperature ceramics.This development is poised to provide robust technical support for the use of ultrahigh temperature ceramics in non-ablative thermal protective systems,partic-ularly in the construction of hypersonic vehicles,where ultrahigh temperature resilience is crucial.展开更多
Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.T...Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.This study investigates the effects of Ti Cu precursor compositions on dealloying behavior and microstructural evolution in liquid Mg,using Ti_(50)Cu_(50)and Ti_(30)Cu_(70)precursors.The initial microstructure of the precursor significantly influences dealloying kinetics and phase transitions.The single-phase Ti_(50)Cu_(50)precursor exhibits a faster initial dealloying rate due to its homogeneous structure,yet complete dealloying requires 90 min.In contrast,the dualphase Ti_(30)Cu_(70)precursor achieves complete dealloying in 30 min,demonstrating the impact of a higher Cu concentration on accelerating the process kinetics.Additionally,the study explores the coarsening behavior and hardness variations during the LMD process,along with the microstructural characteristics of Mg-Ti composites fabricated from these two precursors.The findings highlight the critical role of precursor composition in tailoring the microstructure and properties of Mg-Ti composites produced through the LMD process,demonstrating its potential for advanced composite material manufacturing.展开更多
The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based pol...The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based polymers and other high-value products.Among the various biowaste materials,lignin has gained significant attention due to its high aromatic carbon content,low cost,and abundance.Lignin is predominantly sourced as a byproduct from the paper industry,available in large quantities from hardwood and softwood,with variations in chemical structure and susceptibility to hydrolysis.This study focuses on softwood lignin obtained through the LignoForce^(TM) technology,comparing the thermal and chemical characteristics,and stability,of a recently produced batch with that of a batch that has been stored for four years.Additionally,the development of lignin-based thermoplastic polymer mixtures using Polyethylene Terephthalate Glycol(PET-G)and a blend of Polycarbonate and Acrylonitrile-Butadiene-Styrene(PC/ABS)with high lignin content(50–60 wt%)is explored,as well as the production of filaments for carbon fiber production.For this purpose,following melt mixing,the lignin-based mixtures were spun into filaments,which were subsequently subjected to thermal stabilization in an oxidative atmosphere.The lignin phase was well distributed in the PET-Gmatrix and the twomaterials presented a good interface,which further improved after thermal treatment under an oxidative atmosphere.After thermal treatment an increase in tensile modulus,tensile strength,and elongation at break of approximately 160%,200%,and 100%,respectively,was observed,confirming the good interface established,and consistent with structural changes such as cross-linking.Conversely,the PC/ABS blend did not form a good interface with the lignin domains after melt mixing.Although the interactions improved after thermal treatment,the tensile strength and elongation at break decreased by approximately 30%,while themodulus increased by approximately 20%.Overall,the good processability of the lignin/polymer mixtures into filaments,and their physical,chemical,and mechanical characterization before and after thermal oxidation are good indicators of the potential as precursors for carbon fiber production.展开更多
Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,mar...Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,marrow adipogenic lineage precursors(MALPs),and showed that its production of RANKL stimulates bone resorption in young mice using Adipoq-Cre.To exclude developmental defects and to investigate the role of MALPs-derived RANKL in adult bone,we generated inducible reporter mice(Adipoq-CreER Tomato)and RANKL deficient mice(Adipoq-CreER RANKLflox/flox,iCKO).Single cell-RNA sequencing data analysis and lineage tracing revealed that Adipoq+cells contain not only MALPs but also some mesenchymal progenitors capable of osteogenic differentiation.In situ hybridization showed that RANKL mRNA is only detected in MALPs,but not in osteogenic cells.RANKL deficiency in MALPs induced at 3 months of age rapidly increased trabecular bone mass in long bones as well as vertebrae due to diminished bone resorption but had no effect on the cortical bone.Ovariectomy(OVX)induced trabecular bone loss at both sites.RANKL depletion either before OVX or at 6 weeks post OVX protected and restored trabecular bone mass.Furthermore,bone healing after drill-hole injury was delayed in iCKO mice.Together,our findings demonstrate that MALPs play a dominant role in controlling trabecular bone resorption and that RANKL from MALPs is essential for trabecular bone turnover in adult bone homeostasis,postmenopausal bone loss,and injury repair.展开更多
INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This colla...INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This collapse resulted in a pavement failure of approximately 17.9 m in length and covering an area of about 184.3 m^(2)(Chinanews,2024).展开更多
Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection...Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.展开更多
Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system...Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system,and cell membranes and to reveal the effects of SV2A on APP amyloid degradation.Methods Colocalization analysis of APP with specific tagged proteins in the TGN,ensolysosomal system,and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP.APP,β-site amyloid precursor protein cleaving enzyme 1(BACE1)expressions,and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing.Results APP localization was reduced in the TGN,early endosomes,late endosomes,and lysosomes,whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons.Moreover,Arl5b(ADP-ribosylation factor 5b),a protein responsible for transporting APP from the TGN to early endosomes,was upregulated by SV2A.SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis.In addition,products of APP amyloid degradation,including sAPPβ,Aβ1-42,and Aβ1-40,were decreased in SV2A-overexpressed cells.Conclusion These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway,which slows APP amyloid degradation.展开更多
Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the...Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the role of high mobility group box 1(HMGB1)in oligodendrocyte precursor cells(OPCs)in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier(BBB)by using OPC-specific HMGB1 knockout(KO)mice.We found that HMGB1 released from OPCs promotes BBB disruption,subsequently allowing increased immune cell infiltration.The migration of CD4+T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes(OLs).OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS,leading to less damage to the myelin sheath and mitigated EAE progression.CD4+T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs.Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.展开更多
BACKGROUND Differential diagnosis among atypical hyperplasia(AH)(including reparative hyperplasia and intestinal metaplasia),low-grade dysplasia(LGD),high-grade dysplasia(HGD),and adenocarcinoma(AC)in gastric mucosal ...BACKGROUND Differential diagnosis among atypical hyperplasia(AH)(including reparative hyperplasia and intestinal metaplasia),low-grade dysplasia(LGD),high-grade dysplasia(HGD),and adenocarcinoma(AC)in gastric mucosal biopsies is challenging due to histomorphological overlaps,variability in pathological diagnosis consistency,and limited reproducibility.AIM To evaluate the diagnostic utility of P53,Ki67,P504S,and IMP3 in gastric cancer and its precancerous lesions,focusing on their effectiveness in distinguishing AH,LGD,HGD,and AC.METHODS From January 2018 to September 2020,a total of 185 gastric mucosal biopsy specimens were analyzed according to the pathological diagnostic criteria outlined in the World Health Organization Classification of Digestive System Tumors(2019).The specimens were categorized into four groups:AH,LGD,HGD,and AC.Immunohistochemistry was employed to assess the expression status of P53,Ki67,P504S,and IMP3.Intergroup comparisons were performed using theχ^(2)test or Fisher's exact probability test to compare the differences in immunohistochemical markers across the distinct lesion groups.RESULTS The expression rate of P504S was highest in the LGD group(53.3%,16/30),while IMP3 expression was highest in the AC group(41.9%,26/62),followed by the HGD group(33.3%).Significant differences in P504S and IMP3 expression levels were observed among the four lesion groups(P<0.001).Pairwise comparisons revealed statistically significant differences in P504S expression between the AH group and the LGD,HGD,and AC groups(P<0.001),as well as significant variations in IMP3 expression between the AH group and the HGD and AC groups,and between the LGD group and the HGD and AC groups(P<0.001).Additionally,significant correlations were found between P504S and the polarity expression pattern of Ki67,and between IMP3 and the mutation expression pattern of P53(P<0.001).The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC,respectively.CONCLUSION P504S is highly expressed in LGD and is associated with the Ki67“polarity”expression pattern.IMP3 is highly expressed in HGD/AC and is correlated with the P53 mutation expression pattern.The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC,respectively.The rational use of P504S,Ki67,IMP3,and p53 can help distinguish gastric cancer and precancerous lesions,improving the early cancer diagnosis rate.展开更多
To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and agi...To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and aging treatments.A 50 kg ingot was successfully prepared,highlighting the scalability of this innovative process.Microstructural analysis revealed a predominantly lath martensite matrix with a small amount of ferrite in the hot-forged ODS steel,without oxide particle aggregation.Aging at 750℃ resulted in the formation of sub-micron-sized Cr_(23)C_(6) particles at grain boundaries and martensitic lath interfaces,accompanied by a high-density(7.64×1023 m^(-3))nano-scale(~6 nm)Y-Si-O complex oxides after 25 h.Additionally,the hot-forged sample exhibited a high yield strength(871 MPa)but limited ductility(5.0%).Aging treatments led to an increase in ductility but a decrease in yield strength.Notably,prolonged aging maintained the strength level of steels while enhancing ductility,with a 23.3% total elongation observed after 25 h.The novel ZMPP method,preparing high-quality ODS steels with uniform microstructure and good mechanical properties,provided a new avenue for large-scale production of ODS steels.展开更多
Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β...Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.展开更多
C/C-ZrC composites were prepared by precursor infiltration and pyrolysis using the organic zirconium as precursor.The conversion mechanisms of the precursors such as the thermal behavior,structural evolution,phase com...C/C-ZrC composites were prepared by precursor infiltration and pyrolysis using the organic zirconium as precursor.The conversion mechanisms of the precursors such as the thermal behavior,structural evolution,phase composition,microstructure,composition of the precursors and products were analyzed by thermal gravimetric analyzer,Fourier transform infrared spectrometer,X-ray diffraction and scanning electron microscope.The results indicate that the ZrC precursor transforms to inorganic ZrO2 from room temperature to 1200 ℃,then reduces to ZrC at 1600 ℃ through the carbothermal reduction reaction.The microstructure of the C/C-ZrC composites was also investigated.The composites exhibit an interesting structure,a coating composed of ZrC ceramic covers the exterior of the composite,and the ZrC ceramic is embedded in the pores of the matrix inside the composite.展开更多
Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The presen...Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The present study aims to evaluate the effects of tetrahydroxy stilbene glucoside （TSG）, the extract from herbal medicine Polygoni Multiflori, on cognitive impairment and the over-expression of hippocampal amyloid precursor protein （APP） induced by chronic exposure to Al in rats. Methods Rats were treated with 0.3% aluminum chloride （AlCl3） prepared in the drinking water for 90 d. AlCl3-treated animals were then randomly assigned to receive vehicle, TSG （4 g/kg）, or Vitamin E （VE; 40 mg/kg） treatment for 5 months. VE served as a positive control. The effect of TSG was evaluated by passive avoidance task, and APP expression was evaluated by Western blotting. Results Following exposure to AlCl3 for 90 d, animals displayed a striking decrease （〉80%） in step-through latency in the passive avoidance task and a significant increase in the expression of APP in the hippocampus. Both TSG and VE significantly ameliorated the performance impairment in the passive avoidance task, and suppressed the over-expression of APP. Moreover, the effects of TSG, but not of VE, were in a time-dependent manner. Conclusion TSG may possess therapeutic effects against Alzheimer’s disease.展开更多
An novel method on preparation of precursor solution for solvent separation of molybdenum （Mo） and tungsten （W） by hydrogen peroxide （H2O2）-complexation from the ammonium tungstate solution containing high Mo wa...An novel method on preparation of precursor solution for solvent separation of molybdenum （Mo） and tungsten （W） by hydrogen peroxide （H2O2）-complexation from the ammonium tungstate solution containing high Mo was studied. The precursor solution was obtained via evaporation deamination and H202-complex transformation processes. Then it was extracted with a mixture extractant of tri-alkyl phosphine oxide （TRPO） and tributyl phosphate （TBP） to separate Mo and W. The results indicated that the evaporation deamination complex method reduced the acid consumption by more than 90% in comparison with the traditional directly acid regulation complex method. The transformation rates of W and Mo were higher than 95% and the decomposition rate of H202 was less than 15% at a 1.8-1.9 times H202 dosage, 45-50 ℃, initial pH of 1.80-1.90, and transformation volume ratio of 100% for 60 min in the H2O2-complexation transformation process. The minimum extraction rate of W was 2%, the maximum extraction rate of Mo was 82.6% and the highest separation coefficient was 76.7 in a single-stage extraction.展开更多
基金financially supported by the Innovative Youth Talents of Guangdong Education Department Support Program(No.2021KQNCX027)the Youth Innovative Talents Project of Zhanjiang(No.2021E05016)the Program forScientific Research Start-Up Funds of Guangdong Ocean University(Nos.060302122010 and R19047)。
文摘To realize the commercialize of rechargeable Zn-air battery(RZAB),developing metal-free bifunctional electrocatalysts with satisfactory activity for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is one of the emerging issues.Herein,a prawn shells-derived N-enriched porous carbon(PSNC)is synthesized via an ion exchange coupled biomimetic selfsacrificing template strategy.The resulting PSNC displays unique functional components,including the interconnected macro-meso-micropores structure to shorten charge and mass transfer pathway,high content of pyridinic and graphitic nitrogen to construct rich catalytic active site and improve conductivity.As electrocatalysts in alkaline condition,the optimized PSNC-0.8 achieves excellent bifunctional catalytic propriety with a narrow potential gap(ΔE)value of 0.80 V.Meanwhile,PSNC-0.8-based RZAB displays a high peak power density of 176.5 mW·cm^(-2)and considerable cycling durability with a small battery efficiency delay of 6.5%after 480 cycles(320 h).This study enlightens a simple and effective conception to design high-performance metal-free bifunctional electrocatalysts from seafood waste.
基金supported by the National Natural Science Foundation of China(Nos.52374119,42477142 and 42277154)Natural Science Foundation of Jiangsu Province(No.BK20242059)+1 种基金the open fund of State Key Laboratory of Hydraulics and Mountain River Engineering(No.SKHL2306)the High-level Talent Introduction Project of Changzhou University(No.ZMF24020037)。
文摘Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)precursors in different rock types remains poorly understood.This study investigates the AE characteristics and early warning times of rockburst in slate and mica-schist under four LRs(0.05,0.15,0.25,and 0.5 MPa/s)using true triaxial unloading tests.The micro-crack state of the samples was evaluated using entropy,while critical slowing down(CSD)theory was applied to interpret AE precursors.The results reveal that as the LR increases,the rockburst stress of both rocks initially rises and then declines,with mica-schist exhibiting more severe damage and a higher dominance of tensile cracks.Notably,identifying rockburst precursors in mica-schist proved more challenging compared to slate.Among the methods tested,AE amplitude variance outperformed entropy in precursor identification.Additionally,the rockburst early warning time was found to be negatively correlated with the LR,with mica-schist consistently showing shorter warning times than slate.The CSD-derived precursor,due to its enhanced sensitivity,is recommended for early warning systems.These findings provide new insights into the role of LRs in rockburst dynamics and offer practical guidance for improving precursor identification and disaster mitigation strategies.
文摘Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.
文摘The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detection systems often struggle with detecting early-stage threats,particularly in dynamic environments such as IoT,SDNs,and cloud infrastructures.These systems are hindered by high false positive rates,poor adaptability to evolving threats,and reliance on large labeled datasets.To address these challenges,this paper introduces CyberGuard-X,an AI-driven framework designed to identify attack precursors—subtle indicators of malicious intent—before full-scale intrusions occur.CyberGuard-X integrates anomaly detection,time-series analysis,and multi-stage classification within a scalable architecture.The model leverages deep learning techniques such as autoencoders,LSTM networks,and Transformer layers,supported by semi-supervised learning to enhance detection of zero-day and rare threats.Extensive experiments on benchmark datasets(CICIDS2017,CSE-CIC-IDS2018,and UNSW-NB15)demonstrate strong results,including 96.1%accuracy,94.7%precision,and 95.3%recall,while achieving a zero-day detection rate of 84.5%.With an inference time of 12.8 ms and 34.5%latency reduction,the model supports real-time deployment in resource-constrained environments.CyberGuard-X not only surpasses baseline models like LSTM and Random Forest but also enhances proactive threat mitigation across diverse network settings.
基金Projects(51934007,12072363,52004268) supported by the National Natural Science Foundation of ChinaProject(22KJD440002) supported by the Natural Science Fund for Colleges and Universities in Jiangsu Province,China。
文摘This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic response mechanism of coal energy evolution is examined, and the energy instability criterion is established. The validity of the instability criterion is explored from the standpoint of damage progression. The results demonstrate that the energy conversion mechanism undergoes a fundamental alternation under impact disturbance. Moreover, the energy release rate as well as the energy dissipation rate undergo comparable changes across distinct levels of impact disturbance. The distinction between the energy release rate and the energy dissipation rate (DRD) increases as coal mass deformation grows. Prior to coal facing instability and failure, the DRD experienced an inflection point followed by a sharp decrease. In conjunction with the discussion on the damage evolution, the physical and mechanical significance of DRD remains clear, which can essentially describe the whole impact loading process. The phenomenon that the inflection point appears and DRD subsequently suddenly decreases can be employed as the energy criterion prior to the failure of instability. Furthermore, this paper provides significant reference for the prediction of dynamic instability of coal under dynamic disturbance.
基金supported by the Key Program of the National Natural Science Foundation of China(No.52032003)the Major Program of the National Natural Science Foundation of China(No.52293372)+2 种基金the National Natural Science Foundation of China(No.51972082)the National Natural Science Foundation of China(No.52102093)the National Natural Science Foundation of China(No.52172041)and the science foundation of national key laboratory of science and technology on advanced composites in special environments.
文摘The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which hampers their conversion into boride-based ultrahigh temperature ceramics.To tackle these challenges,a serious of pioneering liquid multi-component hafnium-containing ceramic SiHfCB precursors(with different Hf/Si ratios)have been developed.These novel precursors are featured with stable molec-ular structure and high ceramic yield which were successfully created through a novel one-pot polymer-ization process.They present in liquid form and their structure is characterized by C-C bonds forming its main chain with branched chains of O-Si-O,Si-O-Hf,Si-O-B,and B-O-Hf which have untapped advantages including uniform component dispersion,and excellent fluidity.The ceramic yield of SiHfCB precursor with Hf/Si of 0.2 is remarkably up to 68.6 wt.%at 1500℃,and their Hf content exceeded 50 wt.%.Of particular interest,the pyrolyzed product HfB_(2)-SiC nanopowders derived from the SiHfCB precursor with Hf/Si of 0.2,consist of nanopowders in the 40-60 nm range with a density of 5.23 g cm^(−3).Remarkably,this material demonstrates exceptional performance in ultrahigh temperature oxygen-containing environ-ments at 2500℃,showing near-zero ablation with a linear ablation rate of just 2.5×10^(−4) mm s^(−1).Post-ablation analysis of the microstructure reveals that the formation of a lava-like HfO_(2) and HfO_(2)-SiO_(2) oxide layer effectively blocks oxygen penetration and provides excellent oxidation resistance.The inno-vative SiHfCB hafnium-containing ceramic precursor offers a groundbreaking solution for the preparation of lightweight ultrahigh-temperature ceramics.This development is poised to provide robust technical support for the use of ultrahigh temperature ceramics in non-ablative thermal protective systems,partic-ularly in the construction of hypersonic vehicles,where ultrahigh temperature resilience is crucial.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(Nos.RS-2024–00351052 and RS-2024–00450561)。
文摘Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.This study investigates the effects of Ti Cu precursor compositions on dealloying behavior and microstructural evolution in liquid Mg,using Ti_(50)Cu_(50)and Ti_(30)Cu_(70)precursors.The initial microstructure of the precursor significantly influences dealloying kinetics and phase transitions.The single-phase Ti_(50)Cu_(50)precursor exhibits a faster initial dealloying rate due to its homogeneous structure,yet complete dealloying requires 90 min.In contrast,the dualphase Ti_(30)Cu_(70)precursor achieves complete dealloying in 30 min,demonstrating the impact of a higher Cu concentration on accelerating the process kinetics.Additionally,the study explores the coarsening behavior and hardness variations during the LMD process,along with the microstructural characteristics of Mg-Ti composites fabricated from these two precursors.The findings highlight the critical role of precursor composition in tailoring the microstructure and properties of Mg-Ti composites produced through the LMD process,demonstrating its potential for advanced composite material manufacturing.
基金funded by Project Better Plastics—Plastics in a Circular Economy—PPS4(Circularity by Alternative Feedstocks)Grant agreement ID:POCI-01-0247-FEDER-046091RR was funded by FCT through the PhD grant with reference UI/BD/154446/2022.
文摘The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based polymers and other high-value products.Among the various biowaste materials,lignin has gained significant attention due to its high aromatic carbon content,low cost,and abundance.Lignin is predominantly sourced as a byproduct from the paper industry,available in large quantities from hardwood and softwood,with variations in chemical structure and susceptibility to hydrolysis.This study focuses on softwood lignin obtained through the LignoForce^(TM) technology,comparing the thermal and chemical characteristics,and stability,of a recently produced batch with that of a batch that has been stored for four years.Additionally,the development of lignin-based thermoplastic polymer mixtures using Polyethylene Terephthalate Glycol(PET-G)and a blend of Polycarbonate and Acrylonitrile-Butadiene-Styrene(PC/ABS)with high lignin content(50–60 wt%)is explored,as well as the production of filaments for carbon fiber production.For this purpose,following melt mixing,the lignin-based mixtures were spun into filaments,which were subsequently subjected to thermal stabilization in an oxidative atmosphere.The lignin phase was well distributed in the PET-Gmatrix and the twomaterials presented a good interface,which further improved after thermal treatment under an oxidative atmosphere.After thermal treatment an increase in tensile modulus,tensile strength,and elongation at break of approximately 160%,200%,and 100%,respectively,was observed,confirming the good interface established,and consistent with structural changes such as cross-linking.Conversely,the PC/ABS blend did not form a good interface with the lignin domains after melt mixing.Although the interactions improved after thermal treatment,the tensile strength and elongation at break decreased by approximately 30%,while themodulus increased by approximately 20%.Overall,the good processability of the lignin/polymer mixtures into filaments,and their physical,chemical,and mechanical characterization before and after thermal oxidation are good indicators of the potential as precursors for carbon fiber production.
基金supported by NIH grants NIH/NIA R01AG069401(to L.Q.)NIH/NHLBI U54HL165442(to K.T.)P30AR069619(to Penn Center for Musculoskeletal Disorders).
文摘Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,marrow adipogenic lineage precursors(MALPs),and showed that its production of RANKL stimulates bone resorption in young mice using Adipoq-Cre.To exclude developmental defects and to investigate the role of MALPs-derived RANKL in adult bone,we generated inducible reporter mice(Adipoq-CreER Tomato)and RANKL deficient mice(Adipoq-CreER RANKLflox/flox,iCKO).Single cell-RNA sequencing data analysis and lineage tracing revealed that Adipoq+cells contain not only MALPs but also some mesenchymal progenitors capable of osteogenic differentiation.In situ hybridization showed that RANKL mRNA is only detected in MALPs,but not in osteogenic cells.RANKL deficiency in MALPs induced at 3 months of age rapidly increased trabecular bone mass in long bones as well as vertebrae due to diminished bone resorption but had no effect on the cortical bone.Ovariectomy(OVX)induced trabecular bone loss at both sites.RANKL depletion either before OVX or at 6 weeks post OVX protected and restored trabecular bone mass.Furthermore,bone healing after drill-hole injury was delayed in iCKO mice.Together,our findings demonstrate that MALPs play a dominant role in controlling trabecular bone resorption and that RANKL from MALPs is essential for trabecular bone turnover in adult bone homeostasis,postmenopausal bone loss,and injury repair.
基金supported by the National Natural Science Foundation of China(Nos.42371094,41907253)partially supported by the Interdisciplinary Cultivation Program of Xidian University(No.21103240005)the Postdoctoral Fellowship Program of CPSF(No.GZB20240589)。
文摘INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This collapse resulted in a pavement failure of approximately 17.9 m in length and covering an area of about 184.3 m^(2)(Chinanews,2024).
基金supported by the National Natural Science Foundation of China(No.52202090)the Fundamental Research Funds for the Central Universities(No.2082019014).
文摘Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.
基金supported by grants from the State Key Program of the National Natural Science Foundation of China(grant number 82030064)Beijing Hospital Authority Youth Program(grant number QML20230812)+2 种基金Research and Development Foundation of Capital Medical University(grant number PYZ23052)National Natural Science Youth Cultivation Project of Xuanwu Hospital,Capital Medical University(grant number QNPY202317)Capital Medical University Research and Cultivation Fund(grant number PYZ23049).
文摘Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system,and cell membranes and to reveal the effects of SV2A on APP amyloid degradation.Methods Colocalization analysis of APP with specific tagged proteins in the TGN,ensolysosomal system,and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP.APP,β-site amyloid precursor protein cleaving enzyme 1(BACE1)expressions,and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing.Results APP localization was reduced in the TGN,early endosomes,late endosomes,and lysosomes,whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons.Moreover,Arl5b(ADP-ribosylation factor 5b),a protein responsible for transporting APP from the TGN to early endosomes,was upregulated by SV2A.SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis.In addition,products of APP amyloid degradation,including sAPPβ,Aβ1-42,and Aβ1-40,were decreased in SV2A-overexpressed cells.Conclusion These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway,which slows APP amyloid degradation.
基金supported by the National Research Foundation of Korea(NRF)funded by the government of the Republic of Korea[2023R1A2C1004955]the Technology Innovation Program funded by the Ministry of Trade,Industry&Energy(Korea)(20009707)+1 种基金the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1A6A3A01099056)the Korea Institute for Advancement of Technology funded by the Ministry of Trade,Industry and Energy(P0025489).
文摘Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the role of high mobility group box 1(HMGB1)in oligodendrocyte precursor cells(OPCs)in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier(BBB)by using OPC-specific HMGB1 knockout(KO)mice.We found that HMGB1 released from OPCs promotes BBB disruption,subsequently allowing increased immune cell infiltration.The migration of CD4+T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes(OLs).OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS,leading to less damage to the myelin sheath and mitigated EAE progression.CD4+T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs.Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.
基金Supported by The Science and Technology Research Project of Anyang,No.2022C01SF074。
文摘BACKGROUND Differential diagnosis among atypical hyperplasia(AH)(including reparative hyperplasia and intestinal metaplasia),low-grade dysplasia(LGD),high-grade dysplasia(HGD),and adenocarcinoma(AC)in gastric mucosal biopsies is challenging due to histomorphological overlaps,variability in pathological diagnosis consistency,and limited reproducibility.AIM To evaluate the diagnostic utility of P53,Ki67,P504S,and IMP3 in gastric cancer and its precancerous lesions,focusing on their effectiveness in distinguishing AH,LGD,HGD,and AC.METHODS From January 2018 to September 2020,a total of 185 gastric mucosal biopsy specimens were analyzed according to the pathological diagnostic criteria outlined in the World Health Organization Classification of Digestive System Tumors(2019).The specimens were categorized into four groups:AH,LGD,HGD,and AC.Immunohistochemistry was employed to assess the expression status of P53,Ki67,P504S,and IMP3.Intergroup comparisons were performed using theχ^(2)test or Fisher's exact probability test to compare the differences in immunohistochemical markers across the distinct lesion groups.RESULTS The expression rate of P504S was highest in the LGD group(53.3%,16/30),while IMP3 expression was highest in the AC group(41.9%,26/62),followed by the HGD group(33.3%).Significant differences in P504S and IMP3 expression levels were observed among the four lesion groups(P<0.001).Pairwise comparisons revealed statistically significant differences in P504S expression between the AH group and the LGD,HGD,and AC groups(P<0.001),as well as significant variations in IMP3 expression between the AH group and the HGD and AC groups,and between the LGD group and the HGD and AC groups(P<0.001).Additionally,significant correlations were found between P504S and the polarity expression pattern of Ki67,and between IMP3 and the mutation expression pattern of P53(P<0.001).The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC,respectively.CONCLUSION P504S is highly expressed in LGD and is associated with the Ki67“polarity”expression pattern.IMP3 is highly expressed in HGD/AC and is correlated with the P53 mutation expression pattern.The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC,respectively.The rational use of P504S,Ki67,IMP3,and p53 can help distinguish gastric cancer and precancerous lesions,improving the early cancer diagnosis rate.
基金financially supported by the National Natural Science Foundation of China(Nos.52271034,52301058 and 52471042)the National MCF Energy R&D Program of China(No.2018YFE0306102)+1 种基金the China Postdoctoral Science Foundation(No.2023M732183)the Postdoctoral Fellowship Program of CPSF(No.GZB20230399).
文摘To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and aging treatments.A 50 kg ingot was successfully prepared,highlighting the scalability of this innovative process.Microstructural analysis revealed a predominantly lath martensite matrix with a small amount of ferrite in the hot-forged ODS steel,without oxide particle aggregation.Aging at 750℃ resulted in the formation of sub-micron-sized Cr_(23)C_(6) particles at grain boundaries and martensitic lath interfaces,accompanied by a high-density(7.64×1023 m^(-3))nano-scale(~6 nm)Y-Si-O complex oxides after 25 h.Additionally,the hot-forged sample exhibited a high yield strength(871 MPa)but limited ductility(5.0%).Aging treatments led to an increase in ductility but a decrease in yield strength.Notably,prolonged aging maintained the strength level of steels while enhancing ductility,with a 23.3% total elongation observed after 25 h.The novel ZMPP method,preparing high-quality ODS steels with uniform microstructure and good mechanical properties,provided a new avenue for large-scale production of ODS steels.
基金Project supported in part by the Science and Technology Development Plan Project of Jilin Province, China (Grant No. YDZJ202303CGZH022)the National Key Research and Development Program of China (Grant No. 2024YFE0205300)+1 种基金the National Natural Science Foundation of China (Grant No. 62471504)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University) (Grant No. OEMT-2023KF-05)。
文摘Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.
基金Project (2011CB605801) supported by the National Basic Research Program of ChinaProject (CX2012B042) supported by the Graduated Students' Scientific Research Innovation Project in Hunan Province of China
文摘C/C-ZrC composites were prepared by precursor infiltration and pyrolysis using the organic zirconium as precursor.The conversion mechanisms of the precursors such as the thermal behavior,structural evolution,phase composition,microstructure,composition of the precursors and products were analyzed by thermal gravimetric analyzer,Fourier transform infrared spectrometer,X-ray diffraction and scanning electron microscope.The results indicate that the ZrC precursor transforms to inorganic ZrO2 from room temperature to 1200 ℃,then reduces to ZrC at 1600 ℃ through the carbothermal reduction reaction.The microstructure of the C/C-ZrC composites was also investigated.The composites exhibit an interesting structure,a coating composed of ZrC ceramic covers the exterior of the composite,and the ZrC ceramic is embedded in the pores of the matrix inside the composite.
基金supported by the Natural Science Foundation of Hunan Province, China (No.20227)
文摘Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The present study aims to evaluate the effects of tetrahydroxy stilbene glucoside （TSG）, the extract from herbal medicine Polygoni Multiflori, on cognitive impairment and the over-expression of hippocampal amyloid precursor protein （APP） induced by chronic exposure to Al in rats. Methods Rats were treated with 0.3% aluminum chloride （AlCl3） prepared in the drinking water for 90 d. AlCl3-treated animals were then randomly assigned to receive vehicle, TSG （4 g/kg）, or Vitamin E （VE; 40 mg/kg） treatment for 5 months. VE served as a positive control. The effect of TSG was evaluated by passive avoidance task, and APP expression was evaluated by Western blotting. Results Following exposure to AlCl3 for 90 d, animals displayed a striking decrease （〉80%） in step-through latency in the passive avoidance task and a significant increase in the expression of APP in the hippocampus. Both TSG and VE significantly ameliorated the performance impairment in the passive avoidance task, and suppressed the over-expression of APP. Moreover, the effects of TSG, but not of VE, were in a time-dependent manner. Conclusion TSG may possess therapeutic effects against Alzheimer’s disease.
基金Project(2010ZX07212-008) supported by the Major Science and Technology Program for Water Pollution Control and Treatment the China Molybdenum Co., Ltd.for financial support
文摘An novel method on preparation of precursor solution for solvent separation of molybdenum （Mo） and tungsten （W） by hydrogen peroxide （H2O2）-complexation from the ammonium tungstate solution containing high Mo was studied. The precursor solution was obtained via evaporation deamination and H202-complex transformation processes. Then it was extracted with a mixture extractant of tri-alkyl phosphine oxide （TRPO） and tributyl phosphate （TBP） to separate Mo and W. The results indicated that the evaporation deamination complex method reduced the acid consumption by more than 90% in comparison with the traditional directly acid regulation complex method. The transformation rates of W and Mo were higher than 95% and the decomposition rate of H202 was less than 15% at a 1.8-1.9 times H202 dosage, 45-50 ℃, initial pH of 1.80-1.90, and transformation volume ratio of 100% for 60 min in the H2O2-complexation transformation process. The minimum extraction rate of W was 2%, the maximum extraction rate of Mo was 82.6% and the highest separation coefficient was 76.7 in a single-stage extraction.
