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A novel Mg-Gd-y-Zn-Cu-Ni alloy with excellent combination of strength and dissolution via peak-aging treatment

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Journal of Magnesium and Alloys 2023年第2期11卷 720-734页

作者： y.h.liu Z.R.Zhang J.Wang y.Li h.X.Li L.y.Jia J.h.Wang J.S.Zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Dekai Intelligent Casting Co. Ltd.Hebei 072750China

Inferior absolute strength and dissolution properties are the main bottlenecks for the widespread application of dissolvable magnesium alloys in complex working environments for unconventional oil and gas ***,a novel functional peak-aged Mg-9.5Gd-2.7y-0.9Zn-0.8Cu-0.4Ni(wt.%) alloy for fracturing tools is reported,and it possesses an ultimate tensile strength of 457.6 MPa,ultimate compressive strength of 620.7 MPa and dissolution rate of ~43.7 mg·cm^(-2)·h^(-1) in 3 wt.% KCl solutions at 93℃.The excellent strength of the agedalloy is primarily attributed to the combination of grain refinement,long-period stacking ordered(LPSO) strengthening,and precipitation strengthening induced by stacking fault and β’ phase,among which the precipitation strengthening is *** investigations confirm that the corrosion is triggered from the micro-galvanic coupling between the Mg matrix and the cathodic lamellar and block LPSO ***-shaped corrosion pits along with LPSO phases are subsequently formed,significantly accelerating *** β’ precipitates can effectively improve the strength without compromising the dissolution rate because of their nanoscale *** study provides an excellent material selection for dissolvable fracturing tools and presents a strategy by which a synergistic combination of strength and dissolution rate is achieved via peak-aging treatment.

关键词： Dissolvable magnesium alloy Peak-aging treatment Mechanical properties Micro-galvanic corrosion

IMF By and Bz Effect on Propagation of Pc3-4Waves at the Cusp Latitude

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IMF By and Bz Effect on Propagation of Pc3-4Waves at the Cus...

Measurement of Atmospheric Aerosols using the Wide-Range Particle Spectrometer (WPSTM)

中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： y.h.liu F.W.Menk B.J.Fraser Department of Polar Atmospheric and Space Physics Polar Research Institute of China Centre for Space Physics University of NewcastleNSW 2308Australia

Wave number is one of the key parameters to identify wave’s propagation modes and source ***3-4 waves with source regions locating at upstream solar wind usually appear an anti-sunward propagation,westward in the morning and eastward in the afternoon and changed direction around the magnetic local noon as indicated by reversal of the wave number *** on magnetic observation from Antarctic Zhongshan and Davis stations,however,this case occurs only under IMF Bz>*** this case,the reversal location of the propagation direction varied with IMF By component,moving eastward when IMF By>0 and westward IMF Byhe derived azimuthal wave number shows an ambiguous propagation without clear direction *** results can be explained by that both Zhongshan and Davis stations are located at the cusp latitude near the open-closed boundary of the geomagnetic field lines whose location is associated with IMF Bz and can be further driven by the IMF By component in east-west direction.

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Measurement of Atmospheric Aerosols using the Wide-Range Par...

第八届全国气溶胶会议暨第二届海峡两岸气溶胶科技研讨会

作者： Keung S．Woo Francisco J．Romay William D．Dick Benjamin y.h.liu MSP Corporation ShoreviewMN 55126 MSP Corporation ShoreviewMN 55126 MSP Corporation ShoreviewMN 55126 MSP Corporation ShoreviewMN 55126

＜正＞Increases in ambient aerosol concentrations are associated with adverse health effects such as respiratory irritation and changes in pulmonary function. To test hypotheses regarding effects of atmospheric aerosols, it is essential to measure the atmospheric aerosol properties accurately and efficiently. Since atmospheric aerosols are contributed by multiple sources of aerosol with a wide range of particle diameters, it is important to measure atmospheric aerosols from a few nanometers to several microns in particle diameter. The Wide-Range Particle Spectrometer （WPSTM） is a recently introduced commercial aerosol instrument with the unique capability to measure size distributions of aerosols over a diameter range of 0.01 to 10 μm （liu et al. 2005）. A Scanning Mobility Spectrometer （SMS） comprised of a Differential Mobility Analyzer （DMA） and a Condensation Particle Counter （CPC） is used to measure particles from 0.01 to 0.5 μm and a Laser Particle Spectrometer （LPS） is used to measure particles from 0.35 to 10 μm. These components are small enough to fit within a single portable cabinet （-25 kg） with all accompanying control hardware and electronics. No external pumps are required and power consumption is only 150 W. The WPS was tested in the field for semi-continuous atmospheric sampling during extended periods of time as a way to measure the time-evolution of the atmospheric aerosol size distribution in an urban setting. Results from these measurements show that the WPS works well in various ambient conditions with temperature ranging from 11 ℃ to 35 ℃ and relative humidity ranging from 10% to 70%. Detailed diurnal profiles and nucleation events of atmospheric aerosol size distributions were observed using the WPS in these measurements. With its relatively small size, light weight, low power consumption, and user friendliness, the WPS can perform unprecedented aerosol size distribution measurements in a wide particle diameter range （10 nm - 10,000 nm）. The use o

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空气采样和洁净空气高效滤料性能试验

中国卫生工程学 1992年第2期 55-60页

作者：林秉乐 Benjamin y.h.liu 中国预防医学科学院环境卫生与卫生工程研究所 100050 明尼苏达大学机械工程系粒子技术研究室

用新的测试方法检验了国产的四种高效滤料和两种采样滤料,并与美国的同类滤料进行了比较,表明国产高效滤料性能已赶上世界先进水平。国产滤料主要缺陷是脱毛和滤料本底集尘高,需要今后加以克服。

关键词：空气采样测尘滤料

Unusually thick shear-softening surface of micrometer-size metallic glasses

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The Innovation 2021年第2期2卷 174-182页

作者： J.Dong y.huan B.huang J.yi y.h.liu B.A.Sun W.h.Wang h.y.Bai Institute of Physics Chinese Academy of SciencesBeijing 100190China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of SciencesBeijing 100190China Institute of Materials School of Materials Science and EngineeringShanghai UniversityShanghai 200444China Songshan Lake Materials Laboratory DongguanGuangdong 523808China

The surface of glass is crucial for understanding many fundamental processes in glassy solids.A common notion is that a glass surface is a thin layer with liquid-like atomic dynamics and a thickness of a few tens of ***,we measured the shear modulus at the surface of both millimeter-size and micrometer-size metallic glasses(MGs)through high-sensitivity torsion *** found a pronounced shear-modulus softening at the surface of *** with the bulk,the maximum decrease in the surface shear modulus(G)for the micro-scale MGs reaches~27%,which is close to the decrease in the G upon glass transition,yet it still behaves ***,the surface thickness estimated from the shear-modulus softening is at least 400 nm,which is approximately one order of magnitude larger than that revealed from the glass *** unusually thick surface is also confirmed by measurements using X-ray nano-computed tomography,and this may account for the brittle-to-ductile transition of the MGs with size *** unique and unusual properties at the surface of the micrometer-size MGs are physically related to the negative pressure effect during the thermoplastic formation process,which can dramatically reduce the density of the proximate surface region in the supercooled liquid state.

关键词： glass surface shear modulus torsion metallic glasses

Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： y.h.Zhang h.Li Z.W.yang X.liu Q.F.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of high-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

A perspective on age-related changes in cell environment and risk of neurodegenerative diseases

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Neural Regeneration Research 2024年第4期19卷 719-720页

作者： Alice y.liu Department of Cell Biology and Neuroscience Rutgers State University of New JerseyPiscatawayNJUSA

“Age-related neurodegenerative disease”underscores human age as the primary risk factor for disease development:Alzheimer’s,Parkinson’s,and huntington’s disease(hD)as *** for the age-dependent delay in disease manifestation,in particular for autosomal dominant forms of the disease,and the underlying cause(s)of specific neuron dysfunction and death to manifest as memory loss,anxiety,depression,and agitation in disease subjects remain *** are interested in understanding age-related changes in cell environment that can modulate the structure,function,aggregation.

关键词： huntington Alzheimer death

Rational design of AgGaS/ZnS/ZnS quantum dots with a near-unity photoluminescence quantum yield via double shelling scheme

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Journal of Materials Science & Technology 2024年第2期169卷 235-242页

作者： h.X.Lu h.liu Z.Z.Fu y.y.Chen h.Q.Dai Z.hu W.L.Zhang R.Q.Guo Institute for Electric Light Sources School of Information Science and TechnologyFudan UniversityShanghai 200433China Institute of Future Lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China yiwu Research Institute of Fudan University YiwuZhejiang 322000China Zhongshan-Fudan Joint Innovation Center Zhongshan 528437China

In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS shell,thereby facilitating the formation of a thick outer *** the two-step shelling process,the synthesized AgGaS/ZnS/ZnS QDs showed an excellent photoluminescence quantum yield(PLQy)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PLQy reported thus far for AgGaS ***,the effect of halogen ions in Zn precursors on the shelling process was *** was proposed that the capacity of halogen ions to coordinate with the QDs influenced the balance between Zn cation diffusion and ZnS shelling ***,the ZnS shelling reaction was dominant when ZnCl_(2)was employed,while Zn cation diffusion was the dominant process under the I^(−)-rich *** work provides insights into the interfacial restructuring during the ZnS shelling and offers a clear map for the tailored synthesis of core/shell QDs.

关键词： AgGaS Quantum dots Photoluminescence Core/shell Alloyed core/shell interface

Construction of 2D/2D Ti_(3)C_(2)T_(x)MXene/CdS heterojunction with photothermal effect for efficient photocatalytic hydrogen production

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Journal of Materials Science & Technology 2024年第4期171卷 1-9页

作者： T.y.huang Z.yang S.y.yang Z.h.Dai y.J.liu J.h.Liao G.y.Zhong Z.J.Xie y.P.Fang S.S.Zhang Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Laboratory for Lingnan Modern AgricultureCollege of Materials and EnergySouth China Agricultural UniversityGuangzhou 510643China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China School of Chemical Engineering and Energy Technology Guangdong Provincial Key Laboratory of Distributed Energy SystemsDongguan University of TechnologyDongguan 523808China

The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic *** photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor ***,a novel stable Ti_(3)C_(2)T_(x)MXene/CdS heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)CdS nanosheets on 2D MXene interface via a solvothermal *** exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous *** unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the ***,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of *** irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of CdS *** study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.

关键词： Two-dimensional structure heterostructure Photothermal effect Photocatalyst hydrogen evolution