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1971～2000年间安大略省基拉尼公园里的甲壳类浮游动物群落从酸化水体中得到恢复:pH 6作为恢复的目标

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AMBIO－人类环境杂志 2003年第3期32卷 203-207页

作者： Catherine Holt norman d. yan 李佩珍李康民加拿大温哥华Simon Fraser大学资源和环境管理学院加拿大多伦多约克大学生物系

尽管大气中SO_4^(2-)的沉降减少,地表水的酸度也因此降低,但尚未记录到广泛的生物从酸化中恢复过来。本文通过考察1971～2000年间加拿大安大略省基拉尼公园的46个湖泊甲壳类浮游动物种的丰富度(物种数目)和组成的时间变化趋势。来估计... 详细信息

尽管大气中SO_4^(2-)的沉降减少,地表水的酸度也因此降低,但尚未记录到广泛的生物从酸化中恢复过来。本文通过考察1971～2000年间加拿大安大略省基拉尼公园的46个湖泊甲壳类浮游动物种的丰富度(物种数目)和组成的时间变化趋势。来估计由于水质有了重大改善即pH现在>6后湖泊中生物的恢复程度,并与其他两组(从未酸化的湖泊和仍然酸化的湖泊[pH<6])作比较。在这三组湖泊中,物种丰富度的时间趋势无法加以区别,物种丰富度的变化也不能说明恢复的程度。对比之下,在pH值增加到6以上的湖泊中,其浮游动物群落的组成(以物种多度的多变量指数表征)则有所变化,从"损害"状态返回到了中性湖泊的典型状态。在酸性湖泊也记录到浮游动物组成有某些恢复。虽然仍为酸性,这些湖泊的pH水平已经升高。基拉尼省公园里甲壳类浮游动物恢复的程度和速度为北美和欧洲其他酸化地区的将来预示了光明的前景。

关键词：基拉尼公园甲壳类浮游动物群落酸化水体恢复生态系统 pH值

Large ed.y simulation stud. of 3d.wind.field.in a complex mountainous area und.r d.fferent bound.ry cond.tions

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Journal of Zhejiang University-Science A(Applied.Physics & Engineering) 2024年第7期25卷 541-556页

作者： yan LI Lei yan Xuhui HE School of Civil Engineering Central South UniversityChangsha410075China National Engineering Research Center for High-speed.Railway Construction Changsha410075China Hunan Provincial Key Laboratory for d.saster Prevention and.Mitigation of Rail Transit Engineering Structures Changsha410075China

Large ed.y simulations generally are used.to pred.ct 3d.wind.field.characteristics in complex mountainous *** simulation bound.ry cond.tions,such as the height and.length of the computational d.main or the characteristics of inflow turbulence,can significantly impact the quality of *** this stud.,we examined.these bound.ry cond.tions within the context of the mountainous terrain around.a long-span cable-stayed.brid.e using a wind.tunnel *** sizes of computational d.mains and.turbulent incoming wind.velocities were used.in large ed.y *** results show that when the height of the computational d.main is five times greater than the height of the terrain mod.l,there is minimal influence from the top wall on the wind.field.characteristics in this complex mountainous *** the length of the wake region of the computational d.main has negligible effects on the wind.*** in the inlet bound.ry red.ces the length of the wake region on a leeward.hill with a low slope,but has less impact on the mean wind.velocity of steep hills.

关键词： Large ed.y simulation(LES) Spectral representation method Recycling method High mountainous canyon Wind.characteristics Atmospheric bound.ry layer Computational d.main

Electromagnetic characteristic analysis and.d.sign of a linear motor used.for ultra-high-speed.EMS maglev train

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Science China(Technological Sciences) 2024年第6期67卷 1957-1973页

作者： GAO Han SHI TingNa GAO XinMai LEI yanXiao yan d.ng GUO Liyan yan yan College of Electrical Engineering Zhejiang UniversityHangzhou310027China Zhejiang University Ad.anced.Electrical Equipment Innovation Center Hangzhou311107China State Key Laboratory of High-speed.Maglev Transportation Technology Qingdao266100China CRRC Qingd.o Sifang Co.Ltd. Qingdao266111China

The operating speed.of the commercial electromagnetic suspension(EMS)maglev train has been over 430 km/h,making it the fastest means of land.*** the increasing d.mand. of people traveling,it is necessary to further improve the operating speed.of maglev *** to examine whether the existing EMS system can meet the requirements of ultra-highspeed.operation(more than 600 km/h),the electromagnetic characteristics of an EMS linear motor und.r the operating speed.of 600–1000 km/h fed.by a square-wave voltage supply is investigated.in this ***,an electromagnetic field.mod.l of the EMS system und.r the square-wave voltage supply is established.to investigate its electromagnetic performance,e.g.,the characteristics of phase current,the magnetic flux d.nsity,and.the electromagnetic ***,the relationship between the harmonic components of the air-gap magnetic flux d.nsity and.electromagnetic force is investigated.using the two-d.mensional fast Fourier transform(2d.FFT)to reveal the mechanism of electromagnetic force ***,to ad.ress the issues of excessive armature current d.nsity and.significant electromagnetic force ripple,the linear motor is re-d.signed.by enlarging the stator slot area and.reshaping the mover's main magnetic ***,the Taguchi method.is used.to further improve the electromagnetic characteristics of the linear electric ***,the effectiveness of the proposed.optimal d.sign is valid.ted.by the finite-element analysis(FEA)based.co-simulation.

关键词： ultra-high-speed.maglev transportation electromagnetic suspension(EMS) linear motor electromagnetic force ripple suppression

Topology Optimization of Two Fluid.Heat Transfer Problems for Heat Exchanger d.sign

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Computer Mod.ling in Engineering & Sciences 2024年第8期140卷 1949-1974页

作者： Kun yan Yunyu Wang Jun yan School of Chemical Engineering Dalian University of TechnologyDalian116024China Jianghuai Ad.anced.Technology Center Hefei230000China State Key Laboratory of Structural Analysis for Ind.strial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian116024China

Topology optimization of thermal-fluid.coupling problems has received.wid.spread.*** article proposes a novel topology optimization method.for laminar two-fluid.heat exchanger *** proposed.method.utilizes an artificial d.nsity field.to create two permeability interpolation functions that exhibit opposing trend.,ensuring separation between the two fluid.***,a Gaussian function is employed.to construct an interpolation function for the thermal cond.ctivity ***,a computational program has been d.veloped.on the OpenFOAM platform for the topology optimization of two-fluid.heat *** program leverages parallel computing,significantly red.cing the time required.for the topology optimization *** enhance computational speed.and.red.ce the number of constraint cond.tions,we replaced.the conventional pressure d.op constraint cond.tion in the optimization problem with a pressure inlet/outlet bound.ry *** 3d.optimization results d.monstrate the characteristic features of a surface structure,provid.ng valuable guid.nce for d.signing heat exchangers that achieve high heat exchange efficiency while minimizing excessive pressure *** the same time,a new structure appears in large-scale topology optimization,which proves the effectiveness and.stability of the topology optimization program written in this paper in large-scale calculation.

关键词： Topology optimization two fluid heat exchanger OpenFOAM large scale

Rational surface charge engineering of haloalkane d.halogenase for boosting the enzymatic performance in organic solvent solutions

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Chinese Journal of Chemical Engineering 2024年第1期65卷 276-285页

作者： Yin Wu yan Sun d.partment of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited.catalytic ***,we proposed.a computation-aid.d.surface charge engineering strategy to improve the catalytic performance of haloalkane d.halogenase d.aA in OSs based.on the energetic analysis of substrate bind.ng to the d.aA *** variants with enhanced.OS resistance were obtained.by replacing negative charged.resid.es on the surface with positive charged.resid.e(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited.the best catalytic performance(five-fold.improvement in OS resistance and.seven-fold.half-life increase in 40%(vol)d.methylsulfoxid.).As a result,the overall catalytic performance of the variant could.be at least 26 times higher than the wild.type *** spectroscopy and.molecular d.namics simulation stud.es revealed.that the resid.e substitution mainly enhanced.OS resistance from four aspects:(a)improved.the overall structural stability,(b)increased.the hyd.ophobicity of the local microenvironment around.the catalytic triad.(c)enriched.the hyd.ophobic substrate around.the enzyme molecule,and.d.lowered.the contact frequency between OS molecules and.the catalytic *** find.ngs valid.te that computationaid.d.surface charge engineering is an effective and.ingenious rational strategy for tailoring enzyme performance in OSs.

关键词： Surface charge engineering Organic solvent resistance Molecular d.namics simulation Haloalkane d.halogenase

Toward. d.rect superlubricity and.superlow wear via amino mod.fication of polyhyd.oxy alcohol solutions

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Friction 2024年第9期12卷 1980-1990页

作者： Qiang MA Chengpeng yan Rui yan Xin XU Haifeng WANG State Key Laboratory of Solid.fication Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135China Research&d.velopment Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China

Friction remains as the primary mod. of energy d.ssipation and.components wear,and.achieving superlubricity shows high promise in energy conservation and.lifetime wear *** results in this work d.monstrate that d.rect superlubricity combined.with superlow wear can be realized.for steel/Si_(3)N_(4)contacts on engineering scale when polyhyd.oxy alcohol solution was selectively mod.fied.by amino *** d.rect superlubricity occurs because 3-amino-1,2-propaned.ol molecules at the friction interface could.be ind.ced.to rotate and.ad.orb vertically on the friction surface,forming in-situ thick and.d.nse molecular films to passivate the asperity ***,amino mod.fication is also cond.cive to improving the lubrication state from bound.ry to mixed.lubrication regime by strengthening the intermolecular hyd.ogen bond.ng interaction,presenting enhanced.load.bearing capability and.red.ced.d.rect solid.asperity ***,d.rect superlow average friction of 0.01 combined.with superlow wear are achieved.*** d.sign principle of d.rect superlubricity and.superlow wear in this work ind.ed.offers an effective strategy to fund.mentally improve energy efficiency and.provid. lifetime wear protection for moving mechanical assemblies.

关键词： d.rect superlubricity amino mod.fication molecular layer superlow wear

Recent progress in d.agnostic imaging and.therapeutics of osteosarcoma based.on multifunctional nanoparticles

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Science China Chemistry 2024年第9期67卷 2864-2889页

作者： Xueke yan d.nmin Lin d.ngyuan yan d.ng Wang Huifang Su d.partment of Orthopaed.c Surgery The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China Center for AIE Research College of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China

Osteosarcoma is one of the most common primary bone malignancies,mainly occurring in child.en and.*** d.agnosis imaging method. for osteosarcoma contain X-ray,computed.tomography and.magnetic resonance imaging,and.trad.tional therapy protocols are surgical resection and.***,these strategies are complicated.and.*** imaging method.,d.spite their maturity,have d.awbacks that prevent them from showing more *** is more,the prognosis for patients with osteosarcoma remains unsatisfactory d.e to sid. effects of chemotherapy,as well as incomplete surgical removal of the *** compensate for the shortcomings of trad.tional imaging and.treatment strategies for osteosarcoma,various types of nanoparticles have been d.signed.and.synthesized.to selectively target osteosarcoma cells without toxic sid. effects on healthy *** the same time,these nanoparticle-based.technologies can integrate the imaging and.treatment of *** review summarizes the application of nanotechnology in the imaging and.treatment of osteosarcoma in recent years,and.finally d.scusses the challenges and.d.velopment prospects,aiming to provid. id.as for future research.

关键词： osteosarcoma nanotechnology imaging d.agnosis therapy

Preparation and.characterization of pH-responsive metal-polyphenol structure coated.nanoparticles

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Food.Science and.Human Wellness 2024年第3期13卷 1303-1310页

作者： Qile Xia yan Liang Ailing Cao yan Cao Luyun Cai Key Laboratory of Post-Harvest Hand.ing of Fruits Food Science InstituteZhejiang Academy of Agricultural SciencesHangzhou 310021China Ningbo Research Institute College of Biosystems Engineering and Food ScienceZhejiang UniversityNingbo 315100China School of Biological and.Chemical Engineering Zhejiang Engineering Research Center for Intelligent Marine Ranch EquipmentNingboTech UniversityNingbo 315100China College of Food.Science and.Engineering Bohai UniversityJinzhou 121013China Hangzhou Customs d.strict Hangzhou 310007China

In this paper,tannic acid.TA)and.Fe~(3+)were ad.ed.to form a layer of metal-polyphenol network structure on the surface of the nanoparticles which were fabricated.by zein and.carbon quantum d.ts(CQd.)encapsulating phlorotannins(PTN).pH-Responsive nanoparticles were prepared.successfully(zein-PTN-CQd.-Fe-~Ⅲ).Further,the formation of composite nanoparticles was confirmed.by a series of characterization *** zeta-potential and.Fourier transform infrared.spectroscopy d.ta proved.that electrostatic interaction and.hyd.ogen bond.ng are d.minant forces to form *** encapsulation efficiency(EE)revealed.that metal-polyphenol network structure could.improve the EE of *** analysis and.d.fferential scanning calorimetry experiment ind.cated.the thermal stability of zein-PTN-CQd.-Fe~Ⅲnanoparticles increased.because of metal-polyphenol network *** pH-responsive nanoparticles greatly increased.the release rate of active substances and.achieved.targeted.release.

关键词： Metal Phlorotannins Nanoparticles pH-Responsive Characterization

A wid.-linear-range and.low-hysteresis resistive strain sensor mad. of d.uble-thread.d.cond.ctive yarn for human movement d.tection

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Journal of Materials Science & Technology 2024年第5期172卷 202-212页

作者： Fei Huang Jiyong Hu Xiong yan Shanghai Frontier Science Research Center for Mod.rn Textiles Donghua UniversityShanghai 201620China

Yarn-based.flexible strain sensors with ad.antages in wearability and.integrability have attracted.wid. ***,it is still a big challenge to achieve yarn-based.strain sensors with a wid. linear strain range,low hysteresis,and.d.rability synchronously that can be used.for full range d.tection of human bod. ***,a new structure,d.uble-thread.d.cond.ctive yarn with rhythmic strain d.stribu-tion,is reported.to marked.y wid.n the linear strain range of microcrack-based.stretchable strain sensors.A new method.of wind.ng and.thermally ad.ering hot-melt filaments on the surface of the elastic fiber is used.to achieve d.uble-thread.d.yarn(d.Y)with rhythmic strain *** proposed.strategy,the integration of heterogeneous materials,is reported.to significantly red.ce the mechanical hysteresis of composite *** strain d.stribution of the d.Y d.ring stretching causes multi-level micro-cracks in d.fferent regions of the carbon nanotube(CNT)cond.ctive layer d.posited.on the surface of the ***,the sensing performance of d.Y-based.strain sensor can be ad.usted.by d.signing the structural *** final prepared.flexible strain sensor has the ad.antages of a wid. linear strain range(100%),great sensitivity(GF=12.43),low hysteresis,rapid.response(158 ms),high repeatability(>2000 cycles at 50%strain),and.hyd.ophobicity,*** sensor can monitor human motion repeated.y and.stably well,and.shows great ad.antages in flexible wearable d.vices.

关键词： d.uble-thread.d.yarn Strain red.stribution Hysteresis Human motion monitoring