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激光增材制造Inconel 718基复合材料及力学性能
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作者 钟巧芳 李梦洁 +3 位作者 胡燕秋 屈超 张海军 刘江昊 《化学进展》 北大核心 2025年第9期1384-1396,共13页
Inconel 718(IN718)合金具有优异的高温强度、高延展性和良好的耐蚀性,在航空航天、军工及能源等领域有广阔应用前景。然而,IN718合金较低的硬度和耐磨性严重限制了其应用领域拓展。针对此问题,可行的解决策略之一是对IN718合金进行表... Inconel 718(IN718)合金具有优异的高温强度、高延展性和良好的耐蚀性,在航空航天、军工及能源等领域有广阔应用前景。然而,IN718合金较低的硬度和耐磨性严重限制了其应用领域拓展。针对此问题,可行的解决策略之一是对IN718合金进行表面或基体的组成/结构改性。激光增材制造方法可有效地调控复合材料的组成和显微结构,从而优化其综合力学性能。本文首先介绍了IN718基复合材料的性质特点和改性思路,随后明确了IN718基复合材料激光增材制造方法的优越性和局限性,并且概括了激光增材制造IN718基复合材料的显微结构及力学性能的演变规律,最后总结了IN718基复合材料的组成设计、制备方法改进、显微结构调控和力学性能优化等方面的关键科学问题,进而对本领域研究的未来发展方向作出了展望。 展开更多
关键词 IN718基复合材料 激光增材制造 表面改性 基体改性 显微结构 力学性能
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Zhongfeng Xingnao Liquid ameliorates post-stroke cognitive impairment through sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway 被引量:1
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作者 Wenqin Yang Wen Wen +4 位作者 Hao Chen haijun zhang Yun Lu Ping Wang Shijun Xu 《Chinese Journal of Natural Medicines》 2025年第1期77-89,共13页
The activation of the sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing ... The activation of the sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing reactive oxygen species(ROS)levels.Clinical trials have demonstrated that Zhongfeng Xingnao Liquid(ZFXN)ameliorates post-stroke cognitive impairment(PSCI).However,the underlying mechanism,particularly whether it involves protecting mitochondria and inhibiting apoptosis through the SIRT1/Nrf2/HO-1 pathway,remains unclear.This study employed an oxygen-glucose deprivation(OGD)cell model using SHSY5Y cells and induced PSCI in rats through modified bilateral carotid artery ligation(2VO).The effects of ZFXN on learning and memory,neuroprotective activity,mitochondrial function,oxidative stress,and the SIRT1/Nrf2/HO-1 pathway were evaluated both in vivo and in vitro.Results indicated that ZFXN significantly increased the B-cell lymphoma 2(Bcl2)/Bcl2-associated X(Bax)ratio,reduced terminal deoxynucleotidyl transferase-mediated d UTP nickend-labeling(TUNEL)+cells,and markedly improved cognition,synaptic plasticity,and neuronal function in the hippocampus and cortex.Furthermore,ZFXN exhibited potent antioxidant activity,evidenced by decreased ROS and malondialdehyde(MDA)content and increased superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)levels.ZFXN also demonstrated considerable enhancement of mitochondrial membrane potential(MMP),Tom 20 fluorescence intensity,adenosine triphosphate(ATP)and energy charge(EC)levels,and mitochondrial complexⅠandⅢactivity,thereby inhibiting mitochondrial damage.Additionally,ZFXN significantly increased SIRT1 activity and elevated SIRT1,nuclear Nrf2,and HO-1 levels.Notably,these effects were substantially counteracted when SIRT1 was suppressed by the inhibitor EX-527 in vitro.In conclusion,ZFXN alleviates PSCI by activating the SIRT1/Nrf2/HO-1 pathway and preventing mitochondrial damage. 展开更多
关键词 Zhongfeng Xingnao Liquid Post-stroke cognitive impairment Oxidative stress Mitochondrial function Apoptosis Sirtuin1/nuclear factor erythroid 2-related factor 2/heme oxygenase 1 pathway
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Identification and molecular marker development for peel color gene in melon(Cucumis melo L.) 被引量:1
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作者 Jian Ma Guoliang Yuan +4 位作者 Xinyang Xu haijun zhang Yanhong Qiu Congcong Li Huijun zhang 《Journal of Integrative Agriculture》 2025年第7期2589-2600,共12页
Peel color is an important appearance quality of melons that significantly affects consumer preferences.In this study,a near-isogenic line NIL-G(dark green peel)was generated from B8(grey-green peel)and B15(white peel... Peel color is an important appearance quality of melons that significantly affects consumer preferences.In this study,a near-isogenic line NIL-G(dark green peel)was generated from B8(grey-green peel)and B15(white peel).The F_2 population constructed by crossing NIL-G and B15 was used to study the inheritance pattern of peel color,and bulked-segregant analysis sequencing(BSA-seq)was employed to identify the interval in which the target gene was located.Genetic analysis showed that a dominant gene controls the dark green peel trait at maturity.BSAseq and molecular markers were used to localize the candidate gene in a 263.7 kb interval of chromosome 4,which contained the CmAPRR2 gene with known functions.Moreover,allelic sequence analysis revealed four SNP variations of the CmAPRR2 gene in B15,of which SNP.G614331A was located at the junction of the 6th exon and 6th intron.The G-to-A mutation caused alternative splicing of the transcript of CmAPRR2 in B15,generating two transcripts(CmAPRR2-A and CmAPRR2-B)with premature termination codons.Furthermore,the Kompetitive Allele Specific PCR(KASP)marker,APRR2-G/A,was developed based on this SNP and shown to co-segregate with the peel color phenotype in the F_(2) population.Compared to white-peel B15,the expression level of CmAPRR2 in dark green peel NIL-G was higher at each growth stage.Therefore,CmAPRR2 may be the key gene controlling the fruit color of melons.This study identified a novel allelic variant of CmAPRR2 that leads to white peel formation in mature melons.We also provides a theoretical basis for further research on the gene regulatory mechanism of melon peel colors,which promotes using molecular marker-assisted selection to modify melon peel colors in the future. 展开更多
关键词 MELON BSA-seq MAPPING CmAPRR2 peel color KASP marker
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三维石墨烯基材料的制备、结构与性能 被引量:9
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作者 刘杰 曾渊 +2 位作者 张俊 张海军 刘江昊 《化学进展》 SCIE CAS CSCD 北大核心 2019年第5期667-680,共14页
石墨烯具有单层碳原子组成的六方晶系晶体结构及独特的电学、化学、力学和热学性质。然而,由于石墨烯片层之间较强的π-π键和范德华力,导致易团聚或堆积,使其比表面积大幅减小,严重损害其性能。解决上述问题的最有效方法之一是构建具... 石墨烯具有单层碳原子组成的六方晶系晶体结构及独特的电学、化学、力学和热学性质。然而,由于石墨烯片层之间较强的π-π键和范德华力,导致易团聚或堆积,使其比表面积大幅减小,严重损害其性能。解决上述问题的最有效方法之一是构建具有多孔结构的三维石墨烯基材料,不仅保留了石墨烯优秀的导电性能和力学性能等本征特性,而且获得密度低、比表面积大、孔隙率高等结构优点,进而满足吸附剂、催化剂载体、生物传感器及电池与超级电容器电极材料等先进功能材料领域的应用需要。因此,开发三维石墨烯基材料的先进制备方法成为本领域研究的热点方向。本文综述了三维石墨烯基材料的现有制备方法,包括自组装法(水热还原法、化学还原法及冷冻干燥法)、模板法(胶体模板法、模板辅助化学气相沉积法及模板辅助水热还原法)和3D打印法(直写成型法、喷墨打印法、熔融沉积成型法、光固化成型法、选区激光烧结法及选区激光熔融法),总结了上述方法的优点及当前存在的主要问题,并且对三维石墨烯基材料制备技术的发展方向进行了展望。 展开更多
关键词 三维石墨烯基材料 多孔材料 制备 3D 打印 超级电容器
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Comparative effects of selenium-enriched lactobacilli and selenium-enriched yeast on performance,egg selenium enrichment,antioxidant capacity,and ileal microbiota in laying hens
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作者 Jianmin Zhou Uchechukwu Edna Obianwuna +6 位作者 Longfei zhang Yongli Liu haijun zhang Kai Qiu Jing Wang Guanghai Qi Shugeng Wu 《Journal of Animal Science and Biotechnology》 2025年第3期1399-1415,共17页
Background Organic selenium(Se)has gained recognition in poultry nutrition as a feed additive to boost production and Se deposition in eggs and tissues,owing to its high bioavailability,efficient tissue accumulation a... Background Organic selenium(Se)has gained recognition in poultry nutrition as a feed additive to boost production and Se deposition in eggs and tissues,owing to its high bioavailability,efficient tissue accumulation and minimal toxicity.Selenium-enriched yeast(SeY)is a well-established source,while selenium-enriched lactobacilli(SeL),a newer alternative,offers the added benefits of probiotics.This study examined the effects of SeY and SeL on egg quality,antioxidant capacity,Se deposition,and gut health in laying hens.After a two-week pre-treatment with a Sedeficient diet(SeD),450 Hy-Line Brown laying hens(30-week-old)were assigned into five dietary groups with six replicates of 15 hens each.The groups included a SeD,SeD supplemented with 1.5 mg Se/kg from SeY(SeY15),or 1.5,3.0,and 6.0 mg Se/kg from SeL(SeL15,SeL30,SeL60).The feeding trial lasted for 12 weeks.Results SeY15 and SeL15 improved the feed-to-egg ratio(P<0.05)in the latter stages.Haugh units were significantly increased(P<0.05)in the SeY15 and SeL30 groups,while darker yolk color(P<0.05)was observed in the SeY15,SeL15,and SeL60 groups.All Se-supplemented diets increased Se content in whole eggs,albumen,and yolk(P<0.05),while SeL groups showed a dose-dependent effect.Antioxidant enzyme activities increased,and MDA content decreased in the serum(P<0.05),with SeY15 showing the highest GSH-Px levels(P<0.05).SeL60 increased serum alkaline phosphatase and aspartate transaminase,and distorted the liver architecture(P<0.05).Se-diets reduced concentrations of reactive oxygen species(ROS)in the ileum and liver(P<0.05).SeL15 improved the ileal villus height-tocrypt depth ratio(P<0.05).SeY15 and/or SeL15 up-regulated TXNRD1 and SEPHS1 mRNA while down-regulating SCLY expression in the liver.SeY15 altered ileal microbiota by increasing both beneficial and pathogenic bacteria,whereas SeL15 predominantly boosted beneficial bacteria.Conclusion SeL integrates the antioxidant properties of organic Se with the probiotic benefits on gut health,resulting in a performance-enhancing effect comparable to that of SeY.However,high SeL level(6.0 mg Se/kg)compromised productivity and metabolic functions while enhancing Se deposition. 展开更多
关键词 Antioxidant capacity Egg selenium Feed efficiency Gut microbiota Laying hen Selenium-enriched lactobacilli Selenium-enriched yeast
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Key technologies for networking in satellite-terrestrial integrated network
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作者 haijun zhang Sichen LU Xiaoqi zhang 《Chinese Journal of Aeronautics》 2025年第9期267-270,共4页
1.Introduction As a key development of the next-generation spatial information infrastructure,1the Satellite-Terrestrial Integrated Network(STIN)has become a strategic priority actively pursued by major spacefaring na... 1.Introduction As a key development of the next-generation spatial information infrastructure,1the Satellite-Terrestrial Integrated Network(STIN)has become a strategic priority actively pursued by major spacefaring nations and regions,including the United States,Europe,China,and Russia.Specifically,Space X’s Starlink project has deployed over 6750 satellites,2while One Web has completed its initial phase of satellite constellation deployment with more than 600 satellites. 展开更多
关键词 satellite terrestrial integrated network satellite constellation starlink project next generation spatial information infrastructure Starlink OneWeb STIN
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Phytobiotics in poultry:revolutionizing broiler chicken nutrition with plant‑derived gut health enhancers
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作者 Uchechukwu Edna Obianwuna Xinyu Chang +4 位作者 Vivian U.Oleforuh‑Okoleh Patience N.Onu haijun zhang Kai Qiu Shugeng Wu 《Journal of Animal Science and Biotechnology》 2025年第1期1-33,共33页
As the global population continues to expand,the demand for broiler chicken production to supply safe and high-quality meat is increasing.To meet this ever-growing demand,broiler chickens with enhanced growth performa... As the global population continues to expand,the demand for broiler chicken production to supply safe and high-quality meat is increasing.To meet this ever-growing demand,broiler chickens with enhanced growth performance are being developed,but they often face challenges related to oxidative stress,which can adversely affect gut health.Phytobiotics,which are plant-derived feed additives known for their antimicrobial,antioxidant,immune-modulating,and growth-promoting properties,have emerged as promising natural alternatives to synthetic antibiotics.This review consolidates recent advancements in the use of phytobiotics-derived products from leaves,roots,seeds,flowers,and their extracts in broiler diets reared under standard experimental conditions,without the introduction of stressors.The focus is on elucidating the key mechanisms through which phytobiotics improve gut health,includ-ing their effects on gut morphology,integrity,microflora composition,antioxidant capacity,and immune function.The review highlights the potential of phytobiotics to revolutionize broiler nutrition by acting as natural enhancers of gut health.Research findings reveal that phytobiotics significantly improve intestinal health,and boost growth per-formance,offering a sustainable approach to managing to gut dysfunction.These findings indicate a potential shift in how gut-health related challenges in broilers can be addressed,moving towards natural phytobiotic therapy.How-ever,several challenges persist.Optimizing the dosage of phytobiotics,ensuring consistent performance,and over-coming the limitations related to their extraction and application are key areas requiring further investigation.The review emphasizes the importance of continued research to refine phytobiotic formulations,explore synergistic effects,and incorporate advanced technologies such as AI-driven methods and precision nutrition to tailor feeding strategies more effectively.Additionally,the development of innovative delivery systems,such as nanoencapsula-tion,is suggested as a way to enhance the effectiveness and reliability of phytobiotics.By highlighting the potential of phytobiotics to revolutionize broiler nutrition,this review supports the poultry industry’s shift towards antibiotic-free and sustainable dietary solutions,offering new perspectives on the future of broiler chicken production. 展开更多
关键词 BROILERS Essential oils Gut health Herbs and spices Phytobiotics Plant extracts
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Supplementation of serine in low-gossypol cottonseed meal-based diet improved egg white gelling and rheological properties by regulating ovomucin synthesis and magnum physiological function in laying hens
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作者 Jianmin Zhou Yu Fu +5 位作者 Uchechukwu Edna Obianwuna Jing Wang haijun zhang Xiubo Li Guanghai Qi Shugeng Wu 《Journal of Integrative Agriculture》 2025年第3期1152-1166,共15页
This study examined the effect of dietary serine(Ser)on egg white quality,ovomucin content of laying hens fed low-gossypol cottonseed meal(LCSM)-based diet and sought to explore the regulatory mechanism underlying the... This study examined the effect of dietary serine(Ser)on egg white quality,ovomucin content of laying hens fed low-gossypol cottonseed meal(LCSM)-based diet and sought to explore the regulatory mechanism underlying the effects.A total of 288 Hy-Line Brown layers were randomly assigned into 3 treatments and respectively offered soybean meal(SBM)-based diet,LCSM-based diet,and LCSM-based diet supplemented with 0.435%L-Ser.Dietary Ser supplementation reversed the decrease in quality indices of albumen,including the proportion of thick albumen(P<0.05),thick-to-thin ratio(P<0.05),albumen height(P<0.05),Haugh unit(P<0.05),and apparent viscosity that were caused by LCSM intake.Also,dietary Ser supplementation mitigated the LCSM-induced reduction in ovomucin content of the albumen(P<0.05).FT-IR analysis of ovomucin revealed differences in second derivative spectra at 1,200-800 cm^(-1) between birds received SBM-and LCSM-based diets,meanwhile,the α-helix of ovomucin was decreased by LCSM but increased by Ser addition(P<0.05).Furthermore,Ser addition up-regulated the mRNA expression of β-ovomucin in magnum mucosa at 2 and 7.5 h post-oviposition(P<0.05).Ser mitigated the LCSMinduced impairment of magnum epithelium,increased goblet cell counts(P<0.05),and up-regulated the expression of occludin,mucin 2,and the relevant glycosyltransferases for O-glycosylation in magnum mucosa(P<0.05).Conclusively,the alleviating effect of Ser on declining albumen quality due to dietary LCSM,could be explained by the efficacy of Ser in regulating ovomucin synthesis.This regulation occurred at the levels of transcription and posttranscriptional O-glycosylation modification ofβ-ovomucin,while positive effect on magnum morphology and barrier function could also in part account for the ovomucin content.This would provide a promising research direction on the adoption of nutritional interventions for manipulation of egg white quality from perspectives of albumen protein synthesis. 展开更多
关键词 egg white quality low-gossypol cottonseed meal laying hen OVOMUCIN SERINE
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Joint optimization of UAV aided covert edge computing via a deep reinforcement learning framework
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作者 Wei WEI Shu FU +2 位作者 Yujie TANG Yuan WU haijun zhang 《Chinese Journal of Aeronautics》 2025年第10期96-106,共11页
In this work,we consider an Unmanned Aerial Vehicle(UAV)aided covert edge computing architecture,where multiple sensors are scattered with a certain distance on the ground.The sensor can implement several computation ... In this work,we consider an Unmanned Aerial Vehicle(UAV)aided covert edge computing architecture,where multiple sensors are scattered with a certain distance on the ground.The sensor can implement several computation tasks.In an emergency scenario,the computational capabilities of sensors are often limited,as seen in vehicular networks or Internet of Things(IoT)networks.The UAV can be utilized to undertake parts of the computation tasks,i.e.,edge computing.While various studies have advanced the performance of UAV-based edge computing systems,the security of wireless transmission in future 6G networks is becoming increasingly crucial due to its inherent broadcast nature,yet it has not received adequate attention.In this paper,we improve the covert performance in a UAV aided edge computing system.Parts of the computation tasks of multiple ground sensors are offloaded to the UAV,where the sensors offload the computing tasks to the UAV,and Willie around detects the transmissions.The transmit power of sensors,the offloading proportions of sensors and the hovering height of the UAV affect the system covert performance,we propose a deep reinforcement learning framework to jointly optimize them.The proposed algorithm minimizes the system average task processing delay while guaranteeing that the transmissions of sensors are not detected by the Willie under the covertness constraint.Extensive simulations are conducted to verify the effectiveness of the proposed algorithm to decrease the average task processing delay with comparison with other algorithms. 展开更多
关键词 Covert communication Unmanned aerial vehicle Edge computing Joint optimization Deep reinforcement
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Construction of hollow porous lychee-structured Ni/C/ZnFe_(2)O_(4) microwave-responsive catalysts with rapid efficiently reduction of Cr(VI)ions
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作者 Gaoqian Yuan Ling zhang +6 位作者 Jingzhe zhang Long Dong Xuefeng Liu Yage Li Liang Huang Faliang Li haijun zhang 《Green Energy & Environment》 2025年第10期2086-2096,共11页
Designing catalysts with high reaction efficiency is essential for reducing heavy metal Cr(VI)ions in wastewater via microwave induction.In this paper,a unique microwave-responsive lychee-like Ni/C/ZnFe_(2)O_(4) compo... Designing catalysts with high reaction efficiency is essential for reducing heavy metal Cr(VI)ions in wastewater via microwave induction.In this paper,a unique microwave-responsive lychee-like Ni/C/ZnFe_(2)O_(4) composite catalyst with a double-shell hollow porous heterojunction structure was constructed for the efficient reduction of Cr(VI).Benefiting from the novel hollow porous structure and“carbon nanocage”structure of the Ni/C/ZnFe_(2)O_(4),coupled with excellent electromagnetic wave absorption ability,the prepared lychee-like Ni/C/ZnFe_(2)O_(4) com-posite catalyst could remove up to 98%of Cr(VI)(50 mg L 1,50 mL)after 40 min of microwave irradiation,even in nearly neutral water conditions.Additionally,density functional theory calculations indicated that the heterojunction interface between Ni/C and ZnFe_(2)O_(4) enhances electron transfer from ZnFe_(2)O_(4) to Ni/C,ultimately facilitating the removal of Cr(VI).Furthermore,the incorporation of Ni/C facilitated the 2 acceleration of H ion transfer to*Cr_(2)O_(7),thereby expediting the conversion kinetics of the latter.This research aims to establish a theoretical and experimental foundation for the effective and stable microwave-assisted catalytic reduction of heavy metal Cr(VI)ions,presenting new insights and methods to combat heavy metal contamination. 展开更多
关键词 Microwave-assisted catalysis Cr(VI)reduction Ni/C/ZnFe_(2)O_(4) DFT calculation
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Laser-thermal reduction synthesis of high-entropy alloys towards high-performance pH universal hydrogen evolution reaction
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作者 Yingjie Yu Qi Wang +6 位作者 Xiaohan Li Qiao Xie Ke Xu Shaowei zhang haijun zhang Mingxing Gong Wen Lei 《Nano Materials Science》 2025年第3期400-408,共9页
Owing to their multi-elemental compositions and unique high-entropy mixing states,high-entropy alloy(HEA)nanoparticles(NPs)displaying tunable activities and enhanced stabilities thus have become a rapidly growing area... Owing to their multi-elemental compositions and unique high-entropy mixing states,high-entropy alloy(HEA)nanoparticles(NPs)displaying tunable activities and enhanced stabilities thus have become a rapidly growing area of research in recent years.However,the integration of multiple elements into HEA NPs at the nanoscale remains a formidable challenge,especially when it comes to the precise control of particle size,elemental composition and content.Herein,a simple and universal high-energy laser assisted reduction approach is presented,which achieves the preparation of HEA NPs with a wide range of multi-component,controllable particle sizes and constitution on different substrates within seconds.Laser on carbon nanofibers induced momentary high-temperature annealing(>2000 K and ramping/cooling rates>10^(5)K s^(-1))to successfully decorate HEA NPs up to twenty elements with excellent compatibility for large-scale synthesis(20.0×20.0 cm^(2)of carbon cloth).The IrPdPtRhRu exhibit robust electrocatalytic hydrogen evolution reaction(HER)activities and low overpotentials of 16,28,and 12 mV at a current density of 10 mA cm^(-2)in alkaline(1.0 M KOH),alkaline simulated seawater(1.0 M KOH+0.5 M NaCl),and acidic(0.5 M H_(2)SO_(4))electrolytes,respectively,and excellent stability(7 days and>2000 cycles)at the alkaline HER. 展开更多
关键词 High-entropy alloy nanoparticle Laser assisted reduction Hydrogen production
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Hierarchical Representations Feature Deep Learning for Face Recognition
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作者 haijun zhang Yinghui Chen 《Journal of Data Analysis and Information Processing》 2020年第3期195-227,共33页
Most modern face recognition and classification systems mainly rely on hand-crafted image feature descriptors. In this paper, we propose a novel deep learning algorithm combining unsupervised and supervised learning n... Most modern face recognition and classification systems mainly rely on hand-crafted image feature descriptors. In this paper, we propose a novel deep learning algorithm combining unsupervised and supervised learning named deep belief network embedded with Softmax regress (DBNESR) as a natural source for obtaining additional, complementary hierarchical representations, which helps to relieve us from the complicated hand-crafted feature-design step. DBNESR first learns hierarchical representations of feature by greedy layer-wise unsupervised learning in a feed-forward (bottom-up) and back-forward (top-down) manner and then makes more efficient recognition with Softmax regress by supervised learning. As a comparison with the algorithms only based on supervised learning, we again propose and design many kinds of classifiers: BP, HBPNNs, RBF, HRBFNNs, SVM and multiple classification decision fusion classifier (MCDFC)—hybrid HBPNNs-HRBFNNs-SVM classifier. The conducted experiments validate: Firstly, the proposed DBNESR is optimal for face recognition with the highest and most stable recognition rates;second, the algorithm combining unsupervised and supervised learning has better effect than all supervised learning algorithms;third, hybrid neural networks have better effect than single model neural network;fourth, the average recognition rate and variance of these algorithms in order of the largest to the smallest are respectively shown as DBNESR, MCDFC, SVM, HRBFNNs, RBF, HBPNNs, BP and BP, RBF, HBPNNs, HRBFNNs, SVM, MCDFC, DBNESR;at last, it reflects hierarchical representations of feature by DBNESR in terms of its capability of modeling hard artificial intelligent tasks. 展开更多
关键词 Face Recognition UNSUPERVISED Hierarchical Representations Hybrid Neural Networks RBM Deep Belief Network Deep Learning
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非洲猪瘟疫情背景下我国生猪保险发展现状、功能作用及对策建议探讨 被引量:5
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作者 刘婧 张海军 +2 位作者 吕倩 王熙 吴昊 《猪业科学》 2020年第11期116-119,共4页
生猪产业是农业生产的重要组成部分,是农民收入的重要来源之一,猪肉也是我国城乡居民的主要副食品。2018年8月,我国暴发非洲猪瘟疫情,非洲猪瘟对我国生猪产业造成了较大影响,猪肉产能迅速下降,猪肉价格持续上涨。发展生猪保险,是落实国... 生猪产业是农业生产的重要组成部分,是农民收入的重要来源之一,猪肉也是我国城乡居民的主要副食品。2018年8月,我国暴发非洲猪瘟疫情,非洲猪瘟对我国生猪产业造成了较大影响,猪肉产能迅速下降,猪肉价格持续上涨。发展生猪保险,是落实国家扶持生猪生产政策的重要举措,有利于帮助农户分散转移风险,调动养猪积极性,推动农民增收;有利于提高生猪产业防灾防疫能力,稳定生猪市场供应,保障人民生活;有利于充分发挥保险的社会管理功能,助力国家乡村振兴战略。文章首先简要介绍了我国生猪保险业务发展现状,包括业务规模、保险产品情况及存在问题等,在此基础上结合生产实际情况,对非洲猪瘟背景下我国生猪保险对生猪稳产保供的功能作用进行了详细分析,包括经济补偿、价格稳定、风险管理、融资增信、社会治理和产业扶贫等六大方面。虽然我国生猪保险业务发展取得了较好成效,但仍面临着业务覆盖率偏低、道德风险高、市场化保费费率定价缺乏等难题,所以文章在最后提出了推进我国生猪保险稳定健康发展的相关建议。 展开更多
关键词 生猪保险 非洲猪瘟 产品创新 功能作用 对策建议
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超亲水疏油材料的制备及其油水分离性能 被引量:6
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作者 李孝建 张海军 +3 位作者 李赛赛 张俊 贾全利 张少伟 《化学进展》 SCIE CAS CSCD 北大核心 2020年第6期851-860,共10页
含油污水的随意排放对海洋、沿海周边环境以及人类健康造成了严重的影响。传统的油水分离方法易造成环境二次污染,同时也是对有限资源的一种损耗。因此,如何高效环保地解决含油污水问题具有重要意义。物理过滤/吸附法被认为是一种高效... 含油污水的随意排放对海洋、沿海周边环境以及人类健康造成了严重的影响。传统的油水分离方法易造成环境二次污染,同时也是对有限资源的一种损耗。因此,如何高效环保地解决含油污水问题具有重要意义。物理过滤/吸附法被认为是一种高效环保的分离方法,基于仿生学原理,许多可用于物理选择性分离的超亲油疏水和超亲水疏油材料被制备出来。超亲油疏水材料易被油污染,重复利用率低;相比之下,超亲水疏油材料具有自清洁性且重复利用率高,在油水分离方面具有广阔的应用前景。根据基底材料的选择不同,本文综述了金属基以及高分子基超亲水疏油材料的研究现状,总结了其优缺点,并对今后超亲水疏油材料的研究方向和重点进行了展望。 展开更多
关键词 油水分离材料 超亲水 疏油 微纳米结构
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储能硝酸熔盐的热稳定性分析 被引量:2
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作者 胡憧憬 孙泽 +3 位作者 黄龙 张海军 宋兴福 于建国 《过程工程学报》 CAS CSCD 北大核心 2018年第6期1315-1322,共8页
研究了商业化储能二元混合硝酸熔盐Solar salt(60%NaNO3-40%KNO3)的热稳定性和恒温热稳定性,采用热重法分析了其热分解温度,通过恒温实验考察了处于开放空气气氛中的NaNO3,KNO3和Solar salt在不同温度下的热稳定性,研究了NaNO3和KNO3在S... 研究了商业化储能二元混合硝酸熔盐Solar salt(60%NaNO3-40%KNO3)的热稳定性和恒温热稳定性,采用热重法分析了其热分解温度,通过恒温实验考察了处于开放空气气氛中的NaNO3,KNO3和Solar salt在不同温度下的热稳定性,研究了NaNO3和KNO3在Solar salt高温不稳定性中的作用.结果表明,大于500℃时温度越高,熔盐越不稳定,相同温度下不稳定程度NaNO3>Solar salt>KNO3.温度升高,分解产物NO2-平衡含量增大而达到平衡的时间缩短,O^2-含量很低.Solar salt中硝酸盐热分解和挥发的质量损失比接近1:1,NaNO3是造成体系热分解的主要原因,而KNO3起到抗挥发的作用. 展开更多
关键词 硝酸熔盐 热稳定性 质量损失 机理 热分解 挥发
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耐高温隔热氧化物气凝胶研究进展 被引量:4
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作者 许晴 王昕悦 +3 位作者 蔡伟杰 段红娟 张海军 李少平 《化学进展》 SCIE CAS CSCD 北大核心 2024年第10期1520-1540,共21页
氧化物气凝胶是一种三维纳米多孔材料,具有高孔隙率、高比表面积、低热导率及高熔点等优点,表现出了优异的耐高温以及隔热性能。本文综述了氧化硅、氧化铝、氧化锆气凝胶、二元和多元耐高温隔热氧化物气凝胶及其复合气凝胶的研究进展,... 氧化物气凝胶是一种三维纳米多孔材料,具有高孔隙率、高比表面积、低热导率及高熔点等优点,表现出了优异的耐高温以及隔热性能。本文综述了氧化硅、氧化铝、氧化锆气凝胶、二元和多元耐高温隔热氧化物气凝胶及其复合气凝胶的研究进展,总结了氧化物气凝胶的制备方法和性能,提出了其中存在的问题,并对氧化物气凝胶在耐高温隔热领域的应用进行了展望。 展开更多
关键词 氧化物气凝胶 耐高温 隔热
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纸浆中代表性酚类对二苯并-对-二噁英/二苯并呋喃氯化生成多氯代二噁英的影响 被引量:1
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作者 夏科学 张海军 +2 位作者 倪余文 张亦弛 陈吉平 《环境化学》 CAS CSCD 北大核心 2021年第5期1379-1386,共8页
二苯并-对-二噁英/二苯并呋喃(DBD/F)的直接氯化是纸浆氯漂白过程中形成多氯代二噁英(PCDD/Fs)的重要途径.纸浆中的酚类在氯化漂白过程中也将消耗氯而生成氯化产物.本文在模拟纸浆氯漂白的实验条件下,对实验环境中的DBD/F进行检测,排除... 二苯并-对-二噁英/二苯并呋喃(DBD/F)的直接氯化是纸浆氯漂白过程中形成多氯代二噁英(PCDD/Fs)的重要途径.纸浆中的酚类在氯化漂白过程中也将消耗氯而生成氯化产物.本文在模拟纸浆氯漂白的实验条件下,对实验环境中的DBD/F进行检测,排除了背景DBD/F值对实验的干扰后,研究了纸浆中含量较高的酚类(苯酚、愈创木酚和儿茶酚)对DBD/F氯化生成PCDD/Fs的转化率和同系物模式的影响.发现酚类的加入使DBD/F氯化生成PCDD/Fs的氯化度下降;一定剂量酚类的加入会使体系中DBD/F氯化生成PCDD/Fs的转化率增大,当超出剂量范围后,DBD/F氯化生成PCDD/Fs得到抑制,不同酚类的效应大小各不相同. 展开更多
关键词 酚类 二苯并-对-二噁英/二苯并呋喃 二噁英 氯化
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金融开放的区域经济协调发展效应——以长江三角洲城市群为例 被引量:22
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作者 张海军 岳华 《会计与经济研究》 CSSCI 北大核心 2019年第4期110-126,共17页
金融开放对促进区域经济一体化发展具有显著的作用。通过测算长江三角洲城市群26个城市2005—2016年的金融开放水平,利用面板空间计量模型在地理距离、经济距离和邻接空间三种权重矩阵下对金融开放的经济效应进行了实证分析。研究发现,... 金融开放对促进区域经济一体化发展具有显著的作用。通过测算长江三角洲城市群26个城市2005—2016年的金融开放水平,利用面板空间计量模型在地理距离、经济距离和邻接空间三种权重矩阵下对金融开放的经济效应进行了实证分析。研究发现,金融开放的经济增长效应显著,且存在显著的空间溢出效应;在经济距离权重矩阵下,金融开放水平表现出较强的空间关联性,说明城市之间经济的相对发展水平是影响金融开放溢出效应的原因;在邻近关系上,金融开放也具有显著的空间相关性,表明本地的经济增长除与本地金融开放水平有关外,也与相邻城市金融开放水平有关;但分析认为,地理距离不是决定金融开放经济效应的主要因素;存在金融发展水平提升、产业结构高级化和营商环境改善等实现机制,且金融开放溢出效应的叠加效应强化了该实现机制。据此,本文认为,以五大都市圈为单元进行金融开放,并与相应的发展政策相结合将是促进长江三角洲城市群一体化发展的有效途径。 展开更多
关键词 长江三角洲城市群 金融开放 经济增长 溢出效应 面板空间模型
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木质纤维素气凝胶制备及阻燃改性 被引量:1
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作者 王爽 张鑫 +3 位作者 孙苗 段红娟 张海军 李少平 《化学进展》 SCIE CAS CSCD 北大核心 2024年第4期586-600,共15页
木质纤维素气凝胶具有密度低、孔隙率高、导热系数低等优异性能,被广泛应用于保温隔热、吸附、催化、电磁屏蔽和生物医学等领域。同时木质纤维素也是一种生物基材料,具有绿色、无污染、可再生和可持续的特点。本文首先综述了木材基纤维... 木质纤维素气凝胶具有密度低、孔隙率高、导热系数低等优异性能,被广泛应用于保温隔热、吸附、催化、电磁屏蔽和生物医学等领域。同时木质纤维素也是一种生物基材料,具有绿色、无污染、可再生和可持续的特点。本文首先综述了木材基纤维素和农作物废弃物基纤维素气凝胶的最新研究进展,然后综述了冷冻干燥、超临界干燥和常压干燥制备木质纤维素气凝胶的研究现状。其次,针对木质纤维素气凝胶普遍存在的易燃问题,详述了提高木质纤维素气凝胶阻燃性能的常用方法。最后,提出了木质纤维素气凝胶制备及性能方面存在的主要问题,并对该领域未来的发展方向进行了展望。 展开更多
关键词 气凝胶 木质纤维素 干燥技术 阻燃性能
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Precipitates and alloying elements distribution in nearαtitanium alloy Ti65 被引量:14
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作者 Ke Yue Jianrong Liu +5 位作者 haijun zhang Hui Yu Yuanyuan Song Qingmiao Hu Qingjiang Wang Rui Yang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第1期91-96,共6页
Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and ag... Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and aging process were characterized by using transmission electron microscopy(TEM)and atom probe tomography(APT).Quantitative composition analysis and TEM observation indicate that the silicides fit to(Ti,Zr)6(Sl,Sn)3.Zr exhibits aβ-stabilizing effect in near a titanium alloys but is weaker than otherβstabilizing elements.The enriching tendency of the alloying elements in the retainedβphase is in the order of Zr<Nb<Ta<Mo<W.The experimental results are rationalized by the relative stability of alloying elements in the a andβphases and the mobility of these atoms in the matrix.An enrichment of Si in theα2 phase over theαmatrix phase is noticed,which is attributed to the lower formation energy of Si in theα2 phase. 展开更多
关键词 ATOM probe tomography Titanium alloys Precipitation FIRST-PRINCIPLES calculation ALLOYING elements DISTRIBUTION
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