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Tandem hydroalkylation and deoxygenation of lignin-derived phenolics to synthesize high-density fuels
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作者 Rui Yu Zhensheng Shen +6 位作者 yanan liu Chengxiang Shi Juncong Qu Lun Pan Zhenfeng Huang Xiangwen Zhan g Ji-Jun Zou 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第2期104-109,共6页
Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels usin... Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil. 展开更多
关键词 High-density fuel BIOFUEL Hydrogenation ALKYLATION Lignin Phenolics
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Tracking Regulatory Mechanism of Trace Fe on Graphene Electromagnetic Wave Absorption
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作者 Kaili Zhang Yuhao liu +5 位作者 yanan liu Yuefeng Yan Guansheng Ma Bo Zhong Renchao Che Xiaoxiao Huang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第4期79-96,共18页
Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the... Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials. 展开更多
关键词 Reduced graphene oxide Fe nanosheets Dielectric loss Electromagnetic wave absorption
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The modulatory effect of oolong tea polyphenols on intestinal flora and hypothalamus gene expression in a circadian rhythm disturbance mouse model
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作者 Ruonan Yan Chi-Tang Ho +3 位作者 yanan liu Shengnan Zhan Zufang Wu Xin Zhang 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期748-764,共17页
The interaction between host circadian rhythm and gut microbes through the gut-brain axis provides new clues for tea polyphenols to improve host health.Our present research showed that oolong tea polyphenols(OTP)impro... The interaction between host circadian rhythm and gut microbes through the gut-brain axis provides new clues for tea polyphenols to improve host health.Our present research showed that oolong tea polyphenols(OTP)improved the structural disorder of the intestinal flora caused by continuous darkness,thereby modulating the production of metabolites related to pyruvate metabolism,glycolysis/gluconeogenesis,and tryptophan metabolism to alleviate the steady-state imbalance.After fecal microbiota transplantation from the OTP group,the single-cell transcriptomic analysis revealed that OTP significantly increased the number of hypothalamus cell clusters,up-regulated the number of astrocytes and fibroblasts,and enhanced the expression of circadian rhythm genes Cry2,Per3,Bhlhe41,Nr1d1,Nr1d2,Dbp and Rorb in hypothalamic cells.Our results confirmed that OTP can actively improve the intestinal environmental state as well as internal/peripheral circadian rhythm disorders and cognitive impairment,with potential prebiotic functional characteristics to notably contribute to host health. 展开更多
关键词 Gut microbiota Circadian rhythm Oolong tea polyphenols Single-cell sequencing Metabolism
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Cutting Propagation Technique of Pennisetum purpureum Schum
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作者 Yuanbin HU Jing ZHANG +2 位作者 yanan liu Xiaoyu LIANG Yang JI 《Plant Diseases and Pests》 2024年第2期27-31,共5页
[Objectives]The paper was to study the cutting propagation technique of Pennisetum purpureum Schum and to provide a technical reference for establishing an efficient cutting propagation method.[Methods]Six treatments ... [Objectives]The paper was to study the cutting propagation technique of Pennisetum purpureum Schum and to provide a technical reference for establishing an efficient cutting propagation method.[Methods]Six treatments were set up using P.purpureum cv.Guiminyin and P.purpureum cv.Guimu-1 as test materials,including 1-node oblique insertion,1-node oblique insertion+rooting powder,1-node transverse burial,2-node oblique insertion,2-node oblique insertion+rooting powder and 2-node transverse burial.The following indices were observed and determined for P.purpureum cuttings:emergence rate,rooting rate,root number,longest root length,fresh root weight,plant height,number of tillers,number of leaves,and fresh stem and leaf weight.[Results]In the 2-node cutting+rooting powder treatment,Guiminyin and Guimu-1 exhibited the highest survival rate,root growth indices,and stem and leaf growth indices,with the emergence rates of 94.29%and 90.26%,respectively.The 2-node cutting treatment followed closely behind,while the 1-node cutting treatment had the lowest indices.Under the same treatment,Guimuyin exhibited higher mean values for plant height,number of leaves,fresh stem and leaf weight,longest root length,and fresh root weight compared to Guimu-1.However,it had lower mean number of tillers,and emergence rate and rooting rate of the 1-node cutting treatment compared to Guimu-1.[Conclusions]The P.purpureum cuttings thrived in the 2-node cutting+rooting powder treatment,and the overall cutting effect of Guiminyin was superior to that of Guimu-1. 展开更多
关键词 Pennisetum purpureum Schum CUTTING PROPAGATION Emergence rate
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Current Status of Rn-220 Chamber Carrier Aerosol Modulation Research
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作者 yanan liu Yu Cheng 《Journal of Geoscience and Environment Protection》 2023年第4期30-36,共7页
Radon is the most important source of natural radiation to human beings and the second major causative agent of lung cancer other than smoking. In recent years, the hazards of human exposure to thoron (Rn-220), anothe... Radon is the most important source of natural radiation to human beings and the second major causative agent of lung cancer other than smoking. In recent years, the hazards of human exposure to thoron (Rn-220), another isotope of radon, and its progeny have gained consensus. To accurately evaluate the dose level and hazards of Rn-220 and its progeny, a standard Rn-220 chamber with strong regulation ability for Rn-220 and its progeny needs to be established for the scale or calibration of measurement instruments. This paper describes the hazards, sources, behavioral characteristics of Rn-220 and its progeny, and some representative Rn-220 chambers established in various countries. 展开更多
关键词 THORON Rn-220 Chamber Aerosol Modulation
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近二十年能源结构调整使我国土壤多环芳烃浓度下降 被引量:1
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作者 夏星辉 刘亚男 +3 位作者 张真瑞 席楠楠 保嘉傲 杨志峰 《Engineering》 SCIE EI CAS CSCD 2023年第2期115-123,M0005,共10页
近几十年来,我国在快速发展和工业化的同时,在环境污染防治方面也做出了巨大努力。然而,这些全国性措施(如能源结构调整)对土壤中污染物浓度的影响尚未得到很好的量化。多环芳烃(PAHs)污染在全球范围内引发重要关注,且PAHs排放与能源结... 近几十年来,我国在快速发展和工业化的同时,在环境污染防治方面也做出了巨大努力。然而,这些全国性措施(如能源结构调整)对土壤中污染物浓度的影响尚未得到很好的量化。多环芳烃(PAHs)污染在全球范围内引发重要关注,且PAHs排放与能源结构有关。因此,我们推测我国能源结构的调整可能会降低土壤中PAHs的含量。为了验证这一假设,我们于2008年和2019年在北京54个点位重复采集了土壤样品,分析了美国环境保护署(US EPA)提出的16种优控PAHs化合物(Σ_(16)PAHs)的浓度,并收集了过去20年全国1704个土壤采样点的数据。结果表明,我国Σ_(16)PAHs浓度沿城市-郊区-农村-背景点梯度下降,且Σ_(16)PAHs浓度与区域总产值(GRP)有关,在GRP较低时Σ_(16)PAHs浓度随GRP的增加而增加,随后在GRP达到一定水平时趋于平稳。过去20年,我国土壤Σ_(16)PAH的平均浓度呈下降趋势,其中北京土壤Σ_(16)PAHs的平均浓度从2008年的22.7μg·g^(-1)总有机碳(TOC)显著下降到2019年的10.0μg·g^(-1)TOC。源识别分析推断,土壤PAHs浓度的下降趋势是由于我国煤炭、焦炭、部分油类消费量下降以及电力、天然气等清洁能源消费量上升所致。本研究例证了调整能源结构在降低土壤多环芳烃浓度和改善土壤环境质量中的重要作用。 展开更多
关键词 能源结构调整 环境污染防治 土壤采样 梯度下降 全球范围 近二十年 GRP
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Role of intestinal probiotics in the modulation of lipid metabolism:implications for therapeutic treatments 被引量:1
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作者 Xiaoran Song yanan liu +3 位作者 Xin Zhang Peifang Weng Ruilin Zhang Zufang Wu 《Food Science and Human Wellness》 SCIE CSCD 2023年第5期1439-1449,共11页
Currently, accumulating pieces of evidence indicate that probiotics, living in the gastrointestinal tract, play an important role in regulating host metabolism. As a tool, probiotics have great potential for treating ... Currently, accumulating pieces of evidence indicate that probiotics, living in the gastrointestinal tract, play an important role in regulating host metabolism. As a tool, probiotics have great potential for treating lipid metabolism diseases. However, the relationship between probiotics and abnormal lipid metabolism is still unclear, and the mechanism of action has been become a focus of microbiome research. Therefore, taking intestinal probiotics as the starting point, this article combs the relationship between probiotics and lipid metabolism. Moreover, we discuss the underlying mechanisms of intestinal probiotics regulating lipid metabolism and summarize the therapeutic strategies for abnormal lipids metabolism. This article provides a reference for the further utilization of probiotics in the field of functional foods(food industry). Meanwhile, it will benefit the clinical diagnosis and treatment of lipid metabolism diseases. 展开更多
关键词 PROBIOTICS Lipid metabolism Intestinal flora
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Fabrication of hydrophobic Pd/Al_(2)O_(3)-phosphoric acid via P-O-Al bond for liquid hydrogenation reaction
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作者 Lu Lv Min Zhao +2 位作者 yanan liu Yufei He Dianqing Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第1期232-242,共11页
Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration ... Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration in water environment,result in outstanding decrease in specific surface area and collapse of pore structure.In this work,dodecyl phosphoric acid(PA)is used to modify the surface of Al_(2)O_(3)to obtain a series of hydrophobic material(Al_(2)O_(3)-PA).Based on XPS and NMR analysis,PA is chemically bonded on Al_(2)O_(3)to form PAOAAl bond.Furthermore,BET and WCA results display that Al_(2)O_(3)-1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure.Take it as the substrate to support the Pd nanoparticles,the as-prepared Pd/Al_(2)O_(3)-PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al_(2)O_(3),indicating the accessibility of Pd sites after PA modification.Especially,the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation.This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process.The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation. 展开更多
关键词 Alumina modification Hydrophobic catalyst Phenol hydrogenation Anthraquinone hydrogenation Accessible Pd sites
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A Nitride-Reinforced NbMoTaWHfN Refractory High-Entropy Alloy with Potential Ultra-High-Temperature Engineering Applications
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作者 Yixing Wan Yanhai Cheng +5 位作者 Yongxiong Chen Zhibin Zhang yanan liu Haijun Gong Baolong Shen Xiubing Liang 《Engineering》 SCIE EI CAS CSCD 2023年第11期110-120,共11页
Refractory high-entropy alloys(RHEAs)have promising applications as the new generation of hightemperature alloys in hypersonic vehicles,aero-engines,gas turbines,and nuclear power plants.This study focuses on the micr... Refractory high-entropy alloys(RHEAs)have promising applications as the new generation of hightemperature alloys in hypersonic vehicles,aero-engines,gas turbines,and nuclear power plants.This study focuses on the microstructures and mechanical properties of the NbMoTaW(HfN)_(x)(x=0,0.3,0.7,and 1.0)RHEAs.The alloys consist of multiple phases of body-centered cubic(BCC),hafnium nitride(HfN),or multicomponent nitride(MN)phases.As the x contents increase,the grain size becomes smaller,and the strength gradually increases.The compressive yield strengths of the NbMoTaWHfN RHEA at ambient temperature,1000,1400,and 1800℃ were found to be 1682,1192,792,and 288 MPa,respectively.The high-temperature strength of this alloy is an inspiring result that exceeds the high temperature and strength of most known alloys,including high-entropy alloys,refractory metals,and superalloys.The HfN phase has a significant effect on strengthening due to its high structural stability and sluggish grain coarsening,even at ultra-high temperatures.Its superior properties endow the NbMoTaWHfN RHEA with potential for a wide range of engineering applications at ultra-high temperatures.This work offers a strategy for the design of high-temperature alloys and proposes an ultra-high-temperature alloy with potential for future engineering applications. 展开更多
关键词 Refractory high-entropy alloy High temperature Mechanical property MICROSTRUCTURE Strengthening mechanism
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Bacterial turbulence in gradient confinement
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作者 颜宁哲 谢晨亮 +2 位作者 罗昊 刘亚楠 经光银 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期69-76,共8页
We investigate a novel form of non-uniform living turbulence at an extremely low Reynolds number using a bacterial suspension confined within a sessile droplet. This turbulence differs from homogeneous active turbulen... We investigate a novel form of non-uniform living turbulence at an extremely low Reynolds number using a bacterial suspension confined within a sessile droplet. This turbulence differs from homogeneous active turbulences in two or threedimensional geometries. The heterogeneity arises from a gradient of bacterial activity due to oxygen depletion along the droplet’s radial direction. Motile bacteria inject energy at individual scales, resulting in local anisotropic energy fluctuations that collectively give rise to isotropic turbulence. We find that the total kinetic energy and enstrophy decrease as distance from the drop contact line increases, due to the weakening of bacterial activity caused by oxygen depletion. While the balance between kinetic energy and enstrophy establishes a characteristic vortex scale depending on the contact angle of the sessile drop. The energy spectrum exhibits diverse scaling behaviors at large wavenumber, ranging from k-1/5to k-1,depending on the geometric confinement. Our findings demonstrate how spatial regulation of turbulence can be achieved by tuning the activity of driving units, offering insights into the dynamic behavior of living systems and the potential for controlling turbulence through gradient confinements. 展开更多
关键词 collective motion bacterial turbulence bacterial drop gradient confinement
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Light quality regulates plant biomass and fruit quality through a photoreceptor-dependent HY5-LHC/CYCB module in tomato
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作者 Jiarong Yan Juan liu +17 位作者 Shengdie Yang Chenghao Jiang yanan liu Nan Zhang Xin Sun Ying Zhang Kangyou Zhu Yinxia Peng Xin Bu Xiujie Wang Golam Jalal Ahammed Sida Meng Changhua Tan Yufeng liu Zhouping Sun Mingfang Qi Feng Wang Tianlai Li 《Horticulture Research》 SCIE CSCD 2023年第12期93-107,共15页
Increasing photosynthesis and light capture offers possibilities for improving crop yield and provides a sustainable way to meet the increasing global demand for food.However,the poor light transmittance of transparen... Increasing photosynthesis and light capture offers possibilities for improving crop yield and provides a sustainable way to meet the increasing global demand for food.However,the poor light transmittance of transparent plastic films and shade avoidance at high planting density seriously reduce photosynthesis and alter fruit quality in vegetable crops,and therefore it is important to investigate the mechanisms of light signaling regulation of photosynthesis and metabolism in tomato(Solanum lycopersicum).Here,a combination of red,blue,and white(R1W1B0.5)light promoted the accumulation of chlorophyll,carotenoid,and anthocyanin,and enhanced photosynthesis and electron transport rates by increasing the density of active reaction centers and the expression of the genes LIGHT-HARVESTING COMPLEX B(SlLHCB)and A(SlLHCA),resulting in increased plant biomass.In addition,R1W1B0.5 light induced carotenoid accumulation and fruit ripening by decreasing the expression of LYCOPENEβ-CYCLASE(SlCYCB).Disruption of SlCYCB largely induced fruit lycopene accumulation,and reduced chlorophyll content and photosynthesis in leaves under red,blue,and white light.Molecular studies showed that ELONGATED HYPOCOTYL 5(SlHY5)directly activated SlCYCB,SlLHCB,and SlLHCA expression to enhance chlorophyll accumulation and photosynthesis.Furthermore,R1W1B0.5 light-induced chlorophyll accumulation,photosynthesis,and SlHY5 expression were largely decreased in the slphyb1cry1 mutant.Collectively,R1W1B0.5 light noticeably promoted photosynthesis,biomass,and fruit quality through the photoreceptor(SlPHYB1 and SlCRY1)-SlHY5-SlLHCA/B/SlCYCB module in tomato.Thus,the manipulation of light environments in protected agriculture is a crucial tool to regulate the two vital agronomic traits related to crop production efficiency and fruit nutritional quality in tomato. 展开更多
关键词 CROPS metabolism quality
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Coordinated Rotor-Side Control Strategy for Doubly-FedWind Turbine under Symmetrical and Asymmetrical Grid Faults
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作者 Quanchun Yan Chao Yuan +2 位作者 WenGu yanan liu Yiming Tang 《Energy Engineering》 EI 2023年第1期49-68,共20页
In order to solve the problems of rotor overvoltage,overcurrent and DC side voltage rise caused by grid voltage drops,a coordinated control strategy based on symmetrical and asymmetrical low voltage ride through of ro... In order to solve the problems of rotor overvoltage,overcurrent and DC side voltage rise caused by grid voltage drops,a coordinated control strategy based on symmetrical and asymmetrical low voltage ride through of rotor side converter of the doubly-fed generator is proposed.When the power grid voltage drops symmetrically,the generator approximate equation under steady-state conditions is no longer applicable.Considering the dynamic process of stator current excitation,according to the change of stator flux and the depth of voltage drop,the system can dynamically provide reactive power support for parallel nodes and suppress the rise of DC side voltage and rotor over-current.When the grid voltage drops asymmetrically,the positive and negative sequence components are separated in the rotating coordinate system.The doubly fed generator model is established to suppress the rotor positive sequence current and negative sequence current respectively.At the same time,the output voltage limit of the converter is discussed,and the reference value is adjusted within the allowable output voltage range.In order to adapt to the occurrence of different types of power grid faults and complex operating conditions,a fast switching module of fault type detection and rotor control mode is designed to detect the type of power grid faults and voltage drop depth in real time and switch the rotor side control mode dynamically.Finally,the simulation model of the doubly fed wind turbine is constructed in Matlab/Simulink.The simulation results verify that the proposed control strategy can improve the low-voltage ride through performance of the system when dealing with the symmetrical and asymmetric voltage drop of the power grid and identify the power grid fault type and provide the correct control strategy. 展开更多
关键词 Doubly-fed wind turbines symmetrical faults asymmetrical faults low voltage ride through rotor side control fault type detection
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π-π作用下的VOPc/g-C_3N_4用于有效提升可见光光催化制氢性能(英文) 被引量:2
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作者 刘亚男 马柳波 +4 位作者 申丛丛 王昕 周霄 赵志伟 徐安武 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第2期168-176,共9页
近年来,随着全球科学技术的进步和工业的不断发展,人们的经济生活水平有了极大的提高,但同时也造成能源短缺和环境污染问题,成为21世纪制约经济和社会进一步发展的严重瓶颈,因此开发和研究环保和可再生的绿色能源技术是一项紧迫任务.自... 近年来,随着全球科学技术的进步和工业的不断发展,人们的经济生活水平有了极大的提高,但同时也造成能源短缺和环境污染问题,成为21世纪制约经济和社会进一步发展的严重瓶颈,因此开发和研究环保和可再生的绿色能源技术是一项紧迫任务.自首次报道用二氧化钛为电极、采用光电化学分解水制氢之后,光催化分解水制氢引起了人们极大的兴趣,并被认为是缓解全球能源问题的最有希望的解决方案之一.其中,实现有效的太阳能制氢生产中最关键因素是设计稳定、高效和经济的光催化剂,并且能够利用可见光区进行工作(入射到地球上46%的太阳光谱是可见光).聚合物石墨相氮化物(g-C_3N_4)作为一种对可见光响应的新型无机非金属半导体光催化剂,被认为是一种"可持续"有机半导体材料,目前已并被广泛应用于各种光催化反应中.但是由于其光生电子-空穴在动力学上具有相对较大的复合速率,单纯g-C_3N_4的光催化活性远远达不到人们的要求.因此,应该尽可能的提高电荷转移动力学来抑制g-C_3N_4中光生电荷的复合,从而提高光生电荷从g-C_3N_4转移至反应位点的迁移速率.在前期研究的基础上,本文利用钒氧酞菁(VOPc)分子通过p-p相互作用以修饰g-C_3N_4的表面和电子结构,从而提高其光生电子-空穴的分离效率,最终极大提升其可见光光催化制氢性能.本文采用紫外可见光谱(UV-vis),高分辨透射电镜(HRTEM),傅里叶变换红外光谱(FT-IR), X-射线能谱(XPS),稳态光致发光光谱(PL),时间分辨光致发光光谱(TRPL),光电流和阻抗等一系列表征手段研究了VOPc/g-C_3N_4(VOPc/CN)复合催化剂的结构和性质.FT-IR, XPS及mapping等结果表明, VOPc分子已经成功引入到g-C_3N_4表面且未对其晶相、电子结构及其纳米片结构产生显著影响;UV-vis结果显示, VOPc分子成功引入并通过非共价键的p-p作用连接.总之,引入VOPc分子即拓展了催化剂对可见光的响应区域,又有利于光生载流子的传递和光生电子-空穴对的有效分离.当引入4wt%的VOPc分子时, VOPc/CN复合光催化剂的产氢速率增加至65.52μmolh-1, 420 nm处的量子效率高达6.29%,是单纯g-C_3N_4的6倍.此外,该催化剂在可见光下连续照射反应20 h后,其光催化活性几乎没有降低,表现出良好的光化学稳定性.由于两者LUMO和HOMO轨道之间的良好匹配,在光催化过程中光生电子-空穴在VOPc和g-C_3N_4之间实现了空间分离,有效阻止了光生电子-空穴对的复合,因而g-C_3N_4光催化制氢性能显著提升.同时对比了利用NiS和Ni Px做助剂的g-C_3N_4的可见光光催化制氢性能.结果显示, VOPc/CN复合光催化剂具有较好的光催化性能.总之,本文通过一种简单、经济、有效的方法将两种新兴的功能材料有机地复合在一起,用于可见光照射下高效光催化制氢,为以后合理地开发用于太阳能转换的更为高效经济的材料提供了一个新的思路. 展开更多
关键词 VOPc/g-C3N4 Π-Π作用 可见光催化 制氢 电荷分离效率
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Fe_3O_4/g-C_3N_4复合催化剂增强芬顿/光-芬顿和类过氧化酶反应的活性及稳定性(英文) 被引量:8
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作者 Shafaq Sahar Akif Zeb +2 位作者 刘亚男 Naseeb Ullah 徐安武 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第12期2110-2119,共10页
石墨相的氮化碳(g-C_3N_4)已被广泛用于光催化、水分解、光子检测器、电池、以及光电阴极.与其他光催化材料相比,g-C_3N_4具有价格低廉,易制备,无毒无污染等优点.此外,C_3N_4具有适宜的带隙(2.7 eV),能有效地吸收可见光.有关C_3N_4的光... 石墨相的氮化碳(g-C_3N_4)已被广泛用于光催化、水分解、光子检测器、电池、以及光电阴极.与其他光催化材料相比,g-C_3N_4具有价格低廉,易制备,无毒无污染等优点.此外,C_3N_4具有适宜的带隙(2.7 eV),能有效地吸收可见光.有关C_3N_4的光催化研究很多,但是其降解效率受限于电子空穴对的快速复合.因此,为了提高C_3N_4光催化反应效率,需要对其进行改性.磁铁矿(Fe_3O_4)广泛用于光催化和芬顿/光-芬顿反应.Fe_3O_4晶体具有反式尖晶石结构,其中Fe^(2+)和Fe^(3+)同时存在.研究表明,磁铁矿在酸性条件下催化效果显著,然而,它的比表面积小,随着反应时间的推移,铁离子会溶出,不利于有机物降解反应.因此,近来许多研究着重于磁铁矿复合物的制备,以提高磁铁矿的稳定性及催化性能.本文通过惰性氛围高温焙烧三聚氰胺制备了g-C_3N_4,再通过氯化铁和乙酸钠在乙醇中于180°C溶剂热反应,制备Fe_3O_4纳米粒子,最后通过静电自组装过程制备出Fe_3O_4/g-C_3N_4纳米复合材料.利用X射线衍射(XRD),扫描电子显微镜(SEM)及X射线光电子光谱(XPS)等手段验证其组成和结构.XRD结果表明,Fe_3O_4/g-C_3N_4复合材料中可以清晰看到Fe_3O_4和g-C_3N_4的衍射峰,说明这两种材料的晶相得以保持.SEM和TEM结果表明,Fe_3O_4纳米颗粒很好地附着在g-C_3N_4薄片上.XPS结果表明,氮化碳中存在典型的三种N峰;此外还存在铁的两种价态.光-芬顿活性测试中,相同条件下,Fe_3O_4/g-C_3N_4在60 min内将罗丹明B(RhB)几乎降解完全,而单组份的Fe_3O_4或g-C_3N_4对RhB的降解小于50%.可见,复合后的Fe_3O_4/g-C_3N_4光催化性能得到很大提升.单g-C_3N_4本身由于快速的电子空穴复合以及对双氧水的弱亲和力,因而对Rh B降解效果差.单独的Fe_3O_4由于在中性或者碱性条件下反而会抑制光催化芬顿活性.对于制备的Fe_3O_4/g-C_3N_4复合材料,具有以下优点:(1)电子在Fe^(3+)和g-C_3N_4的LUMO轨道上的转移降低了电子-空穴对的复合;(2)Fe_3O_4均匀分布在g-C_3N_4上,对于H_2O_2的吸附提供了有利的高比表面积;(3)Fe_3O_4和g-C_3N_4之间的界面相互作用使得Fe_3O_4的稳定性提高.通过降解RhB的动力学研究,得到反应速率为0.02 min^(–1),属准一级反应.分析检测结果表明,光-芬顿反应后,RhB分子被彻底矿化降解,没有中间产物生成,最终降解为CO_2和水.同时,通过对辣根过氧化物酶(HRP)模拟催化进行测试,以3,3',5,5'-四甲基联苯胺盐酸盐(TMB)作为基质,同时添加双氧水和Fe_3O_4/g-C_3N_4,在pH值为4.5条件下,TMB可以被有效氧化.实验表明,Fe_3O_4/g-C_3N_4添加量为25 mg/ml时,对TMB氧化性能最佳.复合催化剂还用于多巴胺的催化氧化反应.结果表明,多巴胺的氧化反应速率常数为1.21 min^(–1),属一级动力学反应.总之,复合材料提高了Rh B的光催化降解活性和稳定性;对TMB和HRP亲和性好,表现出高的类过氧化酶反应活性;有效的多巴胺氧化反应表明其有望用于生物基氧化反应中.实验结果表明,本文发展的Fe_3O_4/g-C_3N_4复合材料为其他类型复合材料的制备与应用提供了新的思路. 展开更多
关键词 Fe3O4/g-C3N4纳米复合材料 芬顿反应 染料降解 类辣根过氧化物酶活性 辣根过氧化酶模拟反应
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大学生外向性、活力与生命意义感的关系研究 被引量:2
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作者 李钰婷 任哲 +3 位作者 任凤燕 朱秋锦 刘亚楠 张舒 《心理学进展》 2016年第1期85-90,共6页
目的:探讨大学生的活力感在外向性和生命意义感之间的中介作用。方法:随机在河南省某大学选取249名大学生,采用主观活力量表,中国大五人格问卷简版及生命意义感量表进行测量。结果:外向性与活力均对生命意义感有正向预测作用,控制了活力... 目的:探讨大学生的活力感在外向性和生命意义感之间的中介作用。方法:随机在河南省某大学选取249名大学生,采用主观活力量表,中国大五人格问卷简版及生命意义感量表进行测量。结果:外向性与活力均对生命意义感有正向预测作用,控制了活力后,外向性对生命意义感的正向预测作用不再显著。结论:活力感在外向性和生命意义感之间起完全中介作用。 展开更多
关键词 活力 外向性 生命意义
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Power Allocation and Performance Analysis of the Collaborative NOMA Assisted Relaying Systems in 5G 被引量:8
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作者 Xin liu Xianbin Wang yanan liu 《China Communications》 SCIE CSCD 2017年第1期50-60,共11页
Serving multiple cell-edge mobile terminals poses multifaceted challenges due to the increased transmission power and interferences, which could be overcome by relay communications. With the recent advancement of 5G t... Serving multiple cell-edge mobile terminals poses multifaceted challenges due to the increased transmission power and interferences, which could be overcome by relay communications. With the recent advancement of 5G technologies, non-orthogonal multiple access(NOMA) has been used at relay node to transmit multiple messages simultaneously to multiple cell-edge users. In this paper, a Collaborative NOMA Assisted Relaying(CNAR) system for 5G is proposed by enabling the collaboration of source-relay(S-R) and relay-destination(R-D) NOMA links. The relay node of the CNAR decodes the message for itself from S-R NOMA signal and transmits the remaining messages to the multiple cell-edge users in R-D link. A simplified-CNAR(S-CNAR) system is then developed to reduce the relay complexity. The outage probabilities for both systems are analyzed by considering outage behaviors in S-R and R-D links separately. To guarantee the data rate, the optimal power allocation among NOMA users is achieved by minimizing the outage probability. The ergodic sum capacity in high SNR regime is also approximated. Our mathematical analysis and simulation results show that CNAR system outperforms existing transmission strategies and S-CNAR reaches similar performance with much lower complexity. 展开更多
关键词 5G NOMA RELAYING performance analysis power allocation
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The IL-33/ST2 axis affects tumor growth by regulating mitophagy in macrophages and reprogramming their polarization 被引量:5
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作者 Huadan Xu Dong Li +6 位作者 Jiaoyan Ma Yuanxin Zhao Long Xu Rui Tian yanan liu Liankun Sun Jing Su 《Cancer Biology & Medicine》 SCIE CAS CSCD 2021年第1期172-183,共12页
Objective:Macrophages are a major component of the tumor microenvironment.M1 macrophages secrete pro-inflammatory factors that inhibit tumor growth and development,whereas tumor-associated macrophages(TAMs)mainly exhi... Objective:Macrophages are a major component of the tumor microenvironment.M1 macrophages secrete pro-inflammatory factors that inhibit tumor growth and development,whereas tumor-associated macrophages(TAMs)mainly exhibit an M2 phenotype.Our previous studies have shown that the interleukin-33/ST2(IL-33/ST2)axis is essential for activation of the M1 phenotype.This study investigates the role of the IL-33/ST2 axis in TAMs,its effects on tumor growth,and whether it participates in the mutual conversion between the M1 and M2 phenotypes.Methods:Bone marrow-derived macrophages were extracted from wildtype,ST2 knockout(ST2-/-),and Il33-overexpressing mice and differentiated with IL-4.The mitochondrial and lysosomal number and location,and the expression of related proteins were used to analyze mitophagy.Oxygen consumption rates and glucose and lactate levels were measured to reveal metabolic changes.Results:The IL-33/ST2 axis was demonstrated to play an important role in the metabolic conversion of macrophages from OXPHOS to glycolysis by altering mitophagy levels.The IL-33/ST2 axis promoted enhanced cell oxidative phosphorylation,thereby further increasing M2 polarization gene expression and ultimately promoting tumor growth(P<0.05)(Figure 4).This metabolic shift was not due to mitochondrial damage,because the mitochondrial membrane potential was not significantly altered by IL-4 stimulation or ST2 knockout;however,it might be associated with the m TOR activity.Conclusions:These results clarify the interaction between the IL-33/ST2 pathway and macrophage polarization,and may pave the way to the development of new cancer immunotherapies targeting the IL-33/ST2 axis. 展开更多
关键词 IL-33/ST2 macrophage polarization MITOPHAGY glucose metabolism tumor microenvironment
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Energy consumption and emission mitigation prediction based on data center traffic and PUE for global data centers 被引量:8
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作者 yanan liu Xiaoxia Wei +3 位作者 Jinyu Xiao Zhijie liu Yang Xu Yun Tian 《Global Energy Interconnection》 2020年第3期272-282,共11页
With the rapid development of technologies such as big data and cloud computing,data communication and data computing in the form of exponential growth have led to a large amount of energy consumption in data centers.... With the rapid development of technologies such as big data and cloud computing,data communication and data computing in the form of exponential growth have led to a large amount of energy consumption in data centers.Globally,data centers will become the world’s largest users of energy consumption,with the ratio rising from 3%in 2017 to 4.5%in 2025.Due to its unique climate and energy-saving advantages,the high-latitude area in the Pan-Arctic region has gradually become a hotspot for data center site selection in recent years.In order to predict and analyze the future energy consumption and carbon emissions of global data centers,this paper presents a new method based on global data center traffic and power usage effectiveness(PUE)for energy consumption prediction.Firstly,global data center traffic growth is predicted based on the Cisco’s research.Secondly,the dynamic global average PUE and the high latitude PUE based on Romonet simulation model are obtained,and then global data center energy consumption with two different scenarios,the decentralized scenario and the centralized scenario,is analyzed quantitatively via the polynomial fitting method.The simulation results show that,in 2030,the global data center energy consumption and carbon emissions are reduced by about 301 billion kWh and 720 million tons CO2 in the centralized scenario compared with that of the decentralized scenario,which confirms that the establishment of data centers in the Pan-Arctic region in the future can effectively relief the climate change and energy problems.This study provides support for global energy consumption prediction,and guidance for the layout of future global data centers from the perspective of energy consumption.Moreover,it provides support of the feasibility of the integration of energy and information networks under the Global Energy Interconnection conception. 展开更多
关键词 Data center Pan-Arctic Energy consumption carbon emission Data traffic PUE Global Energy Interconnection
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Inhibition of focal adhesion kinase enhances antitumor response of radiation therapy in pancreatic cancer through CD8+ T cells 被引量:3
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作者 Arsen Osipov Alex B.Blair +14 位作者 Juliane Liberto Jianxin Wang Keyu Li Brian Herbst Yao Xu Shiqi Li Nan Niu Rufiaat Rashid Ding Ding yanan liu Zaiqi Wang Christopher L.Wolfgang Richard A.Burkhart Daniel Laheru Lei Zheng 《Cancer Biology & Medicine》 SCIE CAS CSCD 2021年第1期206-214,共9页
Objective:Pancreatic ductal adenocarcinoma(PDAC)is a deadly malignancy,due in large part to its resistance to conventional therapies,including radiotherapy(RT).Despite RT exerting a modest antitumor response,it has al... Objective:Pancreatic ductal adenocarcinoma(PDAC)is a deadly malignancy,due in large part to its resistance to conventional therapies,including radiotherapy(RT).Despite RT exerting a modest antitumor response,it has also been shown to promote an immunosuppressive tumor microenvironment.Previous studies demonstrated that focal adhesion kinase inhibitors(FAKi)in clinical development inhibit the infiltration of suppressive myeloid cells and T regulatory(T regs)cells,and subsequently enhance effector T cell infiltration.FAK inhibitors in clinical development have not been investigated in combination with RT in preclinical murine models or clinical studies.Thus,we investigated the impact of FAK inhibition on RT,its potential as an RT sensitizer and immunomodulator in a murine model of PDAC.Methods:We used a syngeneic orthotopic murine model to study the effect of FAKi on hypofractionated RT.Results:In this study we showed that IN10018,a small molecular FAKi,enhanced antitumor response to RT.Antitumor activity of the combination of FAKi and RT is T cell dependent.FAKi in combination with RT enhanced CD8+T cell infiltration significantly in comparison to the radiation or FAKi treatment alone(P<0.05).FAKi in combination with radiation inhibited the infiltration of granulocytes but enhanced the infiltration of macrophages and T regs in comparison with the radiation or FAKi treatment alone(P<0.01).Conclusions:These results support the clinical development of FAKi as a radiosensitizer for PDAC and combining FAKi with RT to prime the tumor microenvironment of PDAC for immunotherapy. 展开更多
关键词 Focal adhesion protein-tyrosine kinases RADIOTHERAPY pancreatic neoplasms IMMUNOMODULATION
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Regulation of flowering time in chrysanthemum by the R2R3 MYB transcription factor CmMYB2 is associated with changes in gibberellin metabolism 被引量:5
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作者 Lu Zhu Yunxiao Guan +6 位作者 yanan liu Zhaohe Zhang Muhammad Abuzar Jaffar Aiping Song Sumei Chen Jiafu Jiang Fadi Chen 《Horticulture Research》 SCIE 2020年第1期1515-1524,共10页
The switch from vegetative growth to reproductive growth is a key event in the development of a plant.Here,the product of the chrysanthemum gene CmMYB2,an R2R3 MYB transcription factor that is localized in the nucleus... The switch from vegetative growth to reproductive growth is a key event in the development of a plant.Here,the product of the chrysanthemum gene CmMYB2,an R2R3 MYB transcription factor that is localized in the nucleus,was shown to be a component of the switching mechanism.Plants engineered to overexpress CmMYB2 flowered earlier than did wild-type plants,while those in which CmMYB2 was suppressed flowered later.In both the overexpression and RNAi knockdown plants,a number of genes encoding proteins involved in gibberellin synthesis or signaling,as well as in the response to photoperiod,were transcribed at a level that differed from that in the wild type.Both yeast two-hybrid and bimolecular fluorescence complementation assays revealed that CmMYB2 interacts with CmBBX24,a zinc-finger transcription factor known to regulate flowering by its influence on gibberellin synthesis. 展开更多
关键词 MECHANISM SYNTHESIS SYNTHESIS
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