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Highly Thermally Conductive Polydimethylsiloxane Composites with Controllable 3D GO@f-CNTs Networks via Self-sacrificing Template Method

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Chinese Journal of Polymer Science 2024年第7期42卷 897-906,I0005页

作者： Shuang-Shuang Wang Dian-Ying Feng Zhi-Ming Zhang Xia Liu Kun-Peng Ruan Yong-Qiang guo jun-wei gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an710072China Shandong Institute of Nonmetallic Materials Jinan250031China Queen Mary University of London Engineering School Northwestern Polytechnical UniversityXi’an710072China

Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer *** this work,graphite oxide(GO)and functionalized carbon nanotubes(f-CNTs)are combined to prepare“Line-Plane”-like hetero-structured thermally conductive GO@f-CNTs fillers,which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via selfsacrificing template method based on oxalic ***,thermally conductive GO@f-CNTs/polydimethylsiloxane(PDMS)composites are fabricated via casting *** the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%,GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient(λ,4.00 W·m^(-1)·K^(-1)),about 20 times that of theλof neat PDMS(0.20 W·m^(-1)·K^(-1)),also much higher than theλ(2.44 W·m^(-1)·K^(-1))of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed ***,the obtained GO@f-CNTs/PDMS composites have excellent thermal stability,whoseλdeviation is only about 3%after 500 thermal cycles(20-200℃).

关键词： Polydimethylsiloxane Hetero-structured thermally conductive fillers Self-sacrificing template Thermal conduction networks

Self-Recirculating Casing Treatment for a Radial Compressor

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Chinese Journal of Mechanical Engineering 2009年第4期22卷 567-573页

作者： XIAO jun XU wei gu Chuangang SHU Xinwei Key Laboratory for Power Machinery and Engineering of Ministry of Education Shanghai Jiao Tong University Shanghai 200240 China

Casing treatment is a widely employed technique to increase the stall margins of turbomachineries. In the last several decades, many researches on casing treatment have been carded out. However, the mechanism of its expanding stall margins is still not very clear. Till now, most casing teatment schemes are designed for axial compressors, while the investigations on casing treatments in centrifugal compressors are rarely reported. Moreover, current investigation methods mainly focus on experiments, and perfect theoretic al analysis is not yet feasible. In order to study the effectiveness and further the mechanism of casing treatments in centrifugal compressors, in this paper, a computationally based investigation of the impact of the self-recireulating casing treatment on the performance of a radial compressor is carried out. The results indicate that, by casing bleed and injection, the casing treatment with inclined blades in the cavity expands the stall margin most. At low mass flows, the reversed flow through the cavity with inclined blades develops the counter swirl flow in front of the impeller inlet, which is considered to benefit increasing the pressure rise from the injection port to the bleed port and thereby augment the recirculating flow. At 120% design speed, the stall margin is larger than that at the design speed. However, the cost of extending the stall margin is the reduction of isentropic efficiency. A mended casing treatment by shifting the bleed port upstream is also studied. It is demonstrated that, relative to the original casing treatment, this mend can improve the efficiency evidently notwithstanding a little narrowing of the flow range.

关键词： self-recirculating casing treatment bleed injection stall margin

Thermally Conductive and Insulating Epoxy Composites by Synchronously Incorporating Si-sol Functionalized Glass Fibers and Boron Nitride Fillers

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Chinese Journal of Polymer Science 2020年第7期38卷 730-739,I0006页

作者： Rui-Han Zhang Xue-Tao Shi Lin Tang Zheng Liu jun-Liang Zhang Yong-Qiang guo jun-wei gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

Glass fibers(GFs)/epoxy laminated composites always present weak interlaminar shear strength(ILSS)and low cross-plane thermal conductivity coefficient(λ⊥).In this work,silica-sol,synthesized from tetraethyl orthosilicate(TEOS)and KH-560 via sol-gel method,was employed to functionalize the surface of GFs(Si-GFs).Together with a spherical boron nitride(BNN-30),the thermally conductive BNN-30/Si-GFs/epoxy laminated composites were then *** demonstrate that Si-sol is beneficial to the improvement of mechanical properties for epoxy laminated composites(especially for ILSS).The BNN-30/Si-GFs/epoxy laminated composites with 15 wt%BNN-30 fillers display the optimal comprehensive ***-planeλ(λ//)andλ⊥reach the maximum of 2.37 and 1.07 W.m-1.K-1,146.9%and 132.6%higher than those of SiGFs/epoxy laminated composites(λ//=0.96 W.m-1.K-1 andλ⊥=0.46 W.m-1K-1),respectively,and also about 10.8 and 4.9 times those of pure epoxy resin(λ//=λ⊥,0.22 W.m-1.K-1).And the heat-resistance index(THRI),dielectric constant(ε),dielectric loss(tanδ),breakdown strength(E0),surface resistivity(ρs)as well as volume resistivity(ρv)are 197.3℃,4.95,0.0046,22.3 ***-1,1.8×1014Ω,and 2.1×1014Ω.cm,respectively.

关键词： Thermally conductive composites Glass fibers Epoxy resin Silica-sol Surface functionalization

Impact of atmospheric circulations on droughts and drought propagation over China

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Science China Earth Sciences 2024年第8期67卷 2633-2648页

作者： Ziye gu Lei gu Jiabo YIN wei FANG Lihua XIONG jun guO Ziyue ZENG jun XIA School of Civil and Hydraulic Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Water Resources Engineering and Management Wuhan 430072China Changjiang River Scientific Research Institute Wuhan 430010China

The GRACE satellite mission provides a new approach for monitoring,tracking,and assessing drought conditions by detecting changes in Earth's gravitational fields and inversing signals of terrestrial water storage *** studies of terrestrial water storage anomalies related droughts paid rare attention to the behind atmospheric physical mechanisms,nor quantified the risk propagation patterns between terrestrial water storage deficits and hydrological or agricultural *** this study,we first extract terrestrial water storage(TWS) droughts,hydrological droughts,and agricultural droughts by using multiple variables including TWS from the GRACE/GRACE-FO satellites,runoff and soil moisture from the ERA5-Land reanalysis *** then identify key atmospheric and oceanic oscillation indices affecting water deficits by employing machine learning *** characterize the joint distributions between drought duration and severity by using the Copula function and quantify the risk propagation of hydrological and agricultural droughts to TWS *** results show that:(1) From 2002 to 2021,there is a significant decrasing trend of TWS in China;the WPIO group atmospheric circulation indices(sea surface temperature index within the Western Pacific and Indian Ocean) contributes the most to ***,the sea surface temperature anomalies within the NINO 3.4 region as well as the Western Pacific Warm Pool area index show significantly positive correlation relationships with TWS in southern China;(2) The northwestern China,the Yangtze River basin,and the downstream of the Pearl River basin are the hotspots of TWS ***,the hotspots of hydrological droughts locate in northwestern China and the hotspots of agricultural droughts locate in South China and eastern Tibetan Plateau;(3) The elastic coefficients of hydrological droughts propagating to TWS droughts are higher than those of agricultural droughts,indicating that the TWS droughts

关键词： GRACE satellites Drought Drought propagation Atmospheric circulation Copula function

Thermally Conductive Poly(lactic acid) Composites with Superior Electromagnetic Shielding Performances via 3D Printing Technology

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Chinese Journal of Polymer Science 2022年第3期40卷 248-255,I0006页

作者： Teng-Bo Ma Hao Ma Kun-Peng Ruan Xue-Tao Shi Hua Qiu Sheng-Yuan Gao jun-wei gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China

This work proposes a facile fabrication strategy for thermally conductive graphite nanosheets/poly(lactic acid) sheets with ordered GNPs(o-GNPs/PLA) via fused deposition modeling(FDM) 3 D printing *** combinations of o-GNPs/PLA with Ti_(3) C_(2) T_(x) films prepared by vacuum-assisted filtration were carried out by "layer-by-layer stacking-hot pressing" to be the thermally conductive Ti_(3) C_(2) T_(x)/(oGNPs/PLA) composites with superior electromagnetic interference shielding effectiveness(EMI SE).When the content of GNPs was 18.60 wt%and 4 layers of Ti_(3) C_(2) T_(x)(6.98 wt%) films were embedded,the in-plane thermal conductivity coefficient(λ_(Ⅱ)) and EMI SE(EMI SE_(Ⅱ)) values of the thermally conductive Ti_(3) C_(2) T_(x)/(o-GNPs/P LA) composites significantly increa sed to 3.44 W·m^(-1)·K^(-1) and 65 d B(3.00 mm),increased by 1223.1% and2066.7%,respectively,compared with λ_(Ⅱ)(0.26 W·m^(-1)·K^(-1)) and EMI SE_(Ⅱ)(3 d B) of neat PLA *** work offers a novel and easily route for designing and manufacturing highly thermally conductive polymer composites with superior EMI SE for broader application.

关键词： Polymer-matrix composites(PMCs) Ti_(3)C_(2)T_(x) 3D printing Thermal conductivity Electromagnetic interference(EMI)

Phase separation and transcriptional regulation in cancer development

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Journal of Biomedical Research 2024年第4期38卷 307-321页

作者： Yan gu Ke wei jun Wang Department of Thoracic Surgery Jiangsu Province Hospitalthe First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210029China

Liquid-liquid phase separation,a novel biochemical phenomenon,has been increasingly studied for its medical *** underlies the formation of membrane-less organelles and is involved in many cellular and biological *** transcriptional regulation,dynamic condensates are formed through interactions between transcriptional elements,such as transcription factors,coactivators,and *** is a disease characterized by uncontrolled cell proliferation,but the precise mechanisms underlying tumorigenesis often remain to be *** evidence has linked abnormal transcriptional condensates to several diseases,especially cancer,implying that phase separation plays an important role in *** formed by phase separation may have an effect on gene transcription in *** the present review,we focus on the correlation between phase separation and transcriptional regulation,as well as how this phenomenon contributes to cancer development.

关键词： phase separation transcription regulation cancer super-enhancer condensates

Numerical simulation study on the mold strength of magnetic mold casting based on a coupled electromagnetic-structural method

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China Foundry 2024年第5期21卷 577-587页

作者： wei-li Peng Jian-hua Zhao Cheng gu Ya-jun Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

The properties of the magnetic mold in magnetic mold casting directly determine the quality of the final cast *** this study,the magnetic mold properties in magnetic mold casting,were studied utilizing a coupled electromagnetic-structural method through numerical *** study investigated key factors including equivalent stress,the distribution of tensile and compressive stresses,and the area ratio of tensile *** compared molds made entirely of magnetic materials with those made partially of magnetic *** results indicate that as current increases from 4 A to 8 A,both the initial magnetic mold and the material-replaced magnetic mold initially show an increasing trend in equivalent stress,tensile-compressive stress,and the area ratio of tensile stress,peaking at 6 A before *** material replacement,the area ratio of tensile stress at 6 A decreases to 19.84%,representing a reduction of 29.72%.Magnetic molds comprising a combination of magnetic and non-magnetic materials exhibit sufficient strength and a reduced area ratio of tensile stress compared to those made entirely from magnetic *** study provides valuable insights for optimizing magnetic mold casting processes and offers practical guidance for advancing the application of magnetic molds.

关键词： magnetic mold casting coupled electromagnetic-structural method numerical simulation stress analysis

Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

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Journal of Iron and Steel Research International 2024年第4期31卷 828-837页

作者： gu-jun Chen Sheng-ping He College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Single argon bubble dynamics in liquid steel under Ruhrstahl-Heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure *** simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,*** simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be *** primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic *** the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,*** bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

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Journal of Iron and Steel Research International 2024年第7期31卷 1661-1667页

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-Heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth