Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of hi...Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of high-power semiconductor devices.Based on the ultra-high basal-plane thermal conductivity,graphene is an ideal candidate for preparing high-performance TIMs,preferably to form a vertically aligned structure so that the basal-plane of graphene is consistent with the heat transfer direction of TIM.However,the actual interfacial heat transfer efficiency of currently reported vertically aligned graphene TIMs is far from satisfactory.In addition to the fact that the thermal conductivity of the vertically aligned TIMs can be further improved,another critical factor is the limited actual contact area leading to relatively high contact thermal resistance(20-30 K mm^(2) W^(−1))of the“solid-solid”mating interface formed by the vertical graphene and the rough chip/heat sink.To solve this common problem faced by vertically aligned graphene,in this work,we combined mechanical orientation and surface modification strategy to construct a three-tiered TIM composed of mainly vertically aligned graphene in the middle and micrometer-thick liquid metal as a cap layer on upper and lower surfaces.Based on rational graphene orientation regulation in the middle tier,the resultant graphene-based TIM exhibited an ultra-high thermal conductivity of 176 W m^(−1) K^(−1).Additionally,we demonstrated that the liquid metal cap layer in contact with the chip/heat sink forms a“liquid-solid”mating interface,significantly increasing the effective heat transfer area and giving a low contact thermal con-ductivity of 4-6 K mm^(2) W^(−1) under packaging conditions.This finding provides valuable guidance for the design of high-performance TIMs based on two-dimensional materials and improves the possibility of their practical application in electronic thermal management.展开更多
Grass carp reovirus(GCRV),a disaster agent to aquatic animals,belongs to Genus Aquareovirus of family Reoviridea.Sequence analysis revealed GCRV genome segment 8(s8) was 1 296 bp nucleotides in length encoding an inne...Grass carp reovirus(GCRV),a disaster agent to aquatic animals,belongs to Genus Aquareovirus of family Reoviridea.Sequence analysis revealed GCRV genome segment 8(s8) was 1 296 bp nucleotides in length encoding an inner capsid protein VP6 of about 43kDa.To obtain in vitro non-fusion expression of a GCRV VP6 protein containing a molecular of fluorescence reporter,the recombinant baculovirus,which contained the GCRVs8 and eGFP(enhanced green fluorescence protein) genes,was constructed by using the Bac-to-Bac insect expression system.In this study,the whole GCRVs8 and eGFP genes,amplified by PCR,were constructed into a pFastBacDual vector under polyhedron(PH) and p10 promoters,respectively.The constructed dual recombinant plasmid(pFbDGCRVs8/eGFP) was transformed into DH10Bac cells to obtain recombinant Bacmid(AcGCRVs8/eGFP) by transposition.Finally,the recombinant bacluovirus(vAcGCRVs8/eGFP) was obtained from transfected Sf9 insect cells.The green fluorescence that was expressed by transfected Sf9 cells was initially observed 3 days post transfection,and gradually enhanced and extended around 5 days culture in P1(Passage1) stock.The stable high level expression of recombinant protein was observed in P2 and subsequent passage budding virus(BV) stock.Additionally,PCR amplification from P1 and amplified P2 BV stock further confirmed the validity of the dual-recombinant baculovirus.Our results provide a foundation for expression and assembly of the GCRV structural protein in vitro.展开更多
BACKGROUND Assessment of the vascular status following limb fracture in children is important to evaluate the risk of compartment syndrome,which is an emergency condition.AIM To establish a simple and efficient gradin...BACKGROUND Assessment of the vascular status following limb fracture in children is important to evaluate the risk of compartment syndrome,which is an emergency condition.AIM To establish a simple and efficient grading scale of limb perfusion in children undergoing surgery for limb fracture.METHODS This retrospective study included pediatric patients with a limb fracture and postoperative plaster fixation who were admitted at The Department of Pediatric Orthopedics of Xinhua Hospital between February 2017 and August 2017.The outcome was poor limb perfusion,which is defined as the postoperative use of mannitol.The children were divided into two groups:The normal perfusion group and the poor perfusion group.Key risk factors have been selected by univariable analyses to establish the Grading Scale for Vascular Status.RESULTS A total of 161 patients were included in the study:85 in the normal perfusion group and 76 in the poor perfusion group.There were no significant differences in age,sex,body mass index,ethnicity,cause of fracture,fixation,or site of fracture between the two groups.After surgery,the skin temperature(P=0.048)and skin color(P<0.001)of the affected limb were significantly different between the two groups.The relative risk and 95%confidence interval for skin temperature of the affected limb,skin color,and range of motion of the affected limb are 2.18(1.84-2.59),2.89(2.28-3.66),and 2.16(1.83-2.56),respectively.The grading scale was established based on those three factors(score range:0-3 points).Forty-one patients(32.5%)with score 0 had poor limb perfusion;all patients with scores 1(n=32)and 2(n=3)had poor limb perfusion(both 100%).CONCLUSION In children undergoing surgery for limb fracture,a higher Grading Scale for Vascular Status score is associated with a higher occurrence of poor limb perfusion.A prospective study is required for validation.展开更多
With the fast development of integrated circuit devices as well as batteries with high energy densities,the thermal management of electronic components is becoming increasingly crucial to maintaining their reliable op...With the fast development of integrated circuit devices as well as batteries with high energy densities,the thermal management of electronic components is becoming increasingly crucial to maintaining their reliable operations.Boron nitride nanosheets(BNNS),which have superhigh thermal conductivity along the in-plane direction while remaining electrically insulating,were widely regarded as an ideal filler for preparing high-performance polymer composites to address the‘‘thermal failure''issue.However,due to the instinctive rigidity of BNNS,the nanosheets are unable to form a tightly interfacial contact between the adjoining fillers,resulting in some micro-and nanovoids within the heat transfer pathways and severely limiting further thermal conductivity enhancement for BNNS-based composites.Herein,soft and deformable liquid metal(eutectic gallium-indium,EGaIn)nanoparticles were employed to fill the gaps between the adjacent BNNS with a rational design of mass ratios of BNNS and EGaIn,leading to a strongly synergistic effect with BNNS on thermal conductivity improvement.As a result,the composite film(BNNS:63 wt%and EGaIn:7 wt%)employing cellulose nanofibers(CNF:30 wt%)as the polymer matrix achieves superhigh thermal conductivity along the in-plane direction of up to(90.51±6.71)W·m^(-1)·K^(-1),showing the highest value among the BNNSbased composites with a bi-filler system as far as we know.Additionally,the film can work as a heat spreader for the heat dissipation of high-power light emitting diodes,outperforming tin foil in cooling efficiency.展开更多
Epidemiological studies have shown a high prevalence of low serum testosterone levels in men with cardiovascular disease. Moreover, the tyrosine kinase receptor Axl, the ligand of which is growth arrest-specific prote...Epidemiological studies have shown a high prevalence of low serum testosterone levels in men with cardiovascular disease. Moreover, the tyrosine kinase receptor Axl, the ligand of which is growth arrest-specific protein 6 (GAS6), is expressed in the vasculature, and serum GAS6 levels are associated with endothelial dysfunction and cardiovascular events. Testosterone regulates GAS6 gene transcription directly, which inhibits calcification of vascular smooth muscle cells and provides a mechanistic insight into the cardioprotective action of androgens. This study was designed to determine the correlation between serum GAS6 and testosterone levels in male patients with coronary heart disease (CHD). We recruited 225 patients with CHD and 102 apparently healthy controls, Serum concentrations of GAS6 and soluble Axl were quantified by an enzyme-linked immunosorbent assay. Levels of high-sensitivity C-reactive protein, testosterone, estradiol, and other routine biochemical markers were also measured. Testosterone decreased from 432.69 ± 14.40 to 300.76± 6.23 ng d1-1 (P 〈 0.001) and GAS6 decreased from 16.20± 0.31 to 12.51 ± 0.19 ng ml-1 (P 〈 0.001) in patients with CHD, compared with control subjects. Multiple linear regression analysis showed that serum testosterone and GAS6 levels were positively associated in male patients with CHD. Alterations in GAS6 levels may influence the development of CHD. Downregulation of GAS6/Axl signaling in the presence of low sex hormone levels during disease progression is a potential mechanism by which GAS6 affects CHD. This study provides novel results regarding the influence of sex hormones on serum GAS6 levels in patients with CHD.展开更多
The integration and miniaturization of chips lead to inevitable overheating and increasing electromagnetic interference (EMI) problems, which threaten the performance, stability, and lifetime of electroniccomponents. ...The integration and miniaturization of chips lead to inevitable overheating and increasing electromagnetic interference (EMI) problems, which threaten the performance, stability, and lifetime of electroniccomponents. Therefore, it is important to improve the heat dissipation and EMI shielding performancein device packaging for the steady operation of electronic products. In recent years, due to its intrinsic superior thermal conductivity, proper electrical conductivity, light-weight, and structural adjustability,graphene has been widely used as high thermal and conductive fillers incorporated in the polymer matrix to improve the thermal conductivity and electrical conductivity of composites. This review concludesthe recent development of graphene/polymer composites by using graphene as fillers to improve thethermal conductivity and EMI shielding effectiveness (EMI SE). The structure of graphene embedded inthe composites varies from zero-dimension (0D), one-dimension (1D) to two-dimensions (2D). Moreover,highly thermally and electrically conductive fillers with different dimensions were also modified on thegraphene to improve the composite performance. Finally, this review also makes prospects for the development trend of graphene/polymer composites with high thermal conductivity and EMI SE in the future.展开更多
With the rapid growth in electronic device performance,there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue,thus contributing to the great importance t...With the rapid growth in electronic device performance,there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue,thus contributing to the great importance to develop the graphene framework,which is evaluated as the most promising reinforcements for enhancing the thermal conductivity of polymer.Vacuum filtration is a common method to fabricate graphene framework,whereas,it is available to prepare a framework with centimeter-scale thickness by filtrating the graphene-water dispersion,due to the fact of sample cracking caused by the mismatch of surface tension between graphene and water.In this work,a surfactantassisted strategy was proposed by adjusting the surface tension of the water close to that of graphene first,then performing a conventional filtration process,to fabricate graphene framework.As a result,a thick graphene framework(thickness:3 cm)was successfully prepared,and after embedding into epoxy,the framework endows the composite(13.6 wt%)with a high in-plane thermal conductivities of12.4 W/mK,which is equivalent to≈64 times higher than that of neat epoxy.Our method is simple and compatible with the conventional filtration process,suggesting great potential for the mass-production of graphene framework to meet the practical application requirements.展开更多
Electronic packaging materials and thermal interface materials(TIMs)are widely used in thermal management.In this study,the epoxy composites with core-shell structure SiC@SiO_(2) nanowires(SiC@SiO_(2) NWs)as fillers c...Electronic packaging materials and thermal interface materials(TIMs)are widely used in thermal management.In this study,the epoxy composites with core-shell structure SiC@SiO_(2) nanowires(SiC@SiO_(2) NWs)as fillers could effectively enhance the thermal conductivity of epoxy composites.The unique structure of fillers results in a high thermal conductivity of epoxy composites,which is attributed to good interfacial compatibility epoxy matrix and bridging connections of SiC@SiO_(2) NWs.From neat epoxy to 2.5 wt%loading of SiC@SiO_(2) NWs,the thermal conductivity is significantly increased from 0.218 to 0.391 W m^(−1) K^(−1),increased by 79.4%.In addition,the composite with 2.5 wt%filler possess lower coefficient of thermal expansion and better thermal stability than that of neat epoxy.All these outstanding properties imply that epoxy/SiC@SiO_(2) NWs composites could be the ideal candidate for TIM.展开更多
As the power density of electronic devices increases,there has been an urgent demand to develop highly conductive polymer composites to address the accompanying thermal management issues.Due to the ultra-high intrinsi...As the power density of electronic devices increases,there has been an urgent demand to develop highly conductive polymer composites to address the accompanying thermal management issues.Due to the ultra-high intrinsic thermal conductivity,graphene is considered a very promising filler to improve the thermal conductivity of polymers.However,graphene-based polymer composites prepared by the conventional mixing method generally have limited thermal conductivity,even under high graphene loading,due to the failure to construct efficient heat transfer pathways in the polymer matrix.Here,a spiral graphene framework(SGF)containing continuous and highly ordered graphene microtubes was developed based on a modified CVD method.After embedding into the epoxy(EP)matrix,the graphene microtubes can act as efficient heat pathways,endowing the SGF/EP composites with a high through-plane thermal conductivity of 1.35 W·m^(-1)·K^(-1) at an ultralow graphene loading of 0.86 wt%.This result gives a thermal conductivity enhancement per 1 wt%filler loading of 710%,significantly outperforming various graphene structures as fillers.In addition,we demonstrated the practical application of the SGF/EP composite as a thermal interface material for efficient thermal man-agement of the light-emitting diode(LED).展开更多
A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the...A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection,and the detection limit of aniline can reach5.5 x 10^(-4)mol/L.Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown,which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection.Moreover,for more convenient use,FJU-200 test papers are prepared.Using them,convenient and fast aniline or ultraviolet detection can be realized.The single-crystal X-ray structures show that compared with the original FJU-200,both PhNH_(2)@FJU-200 and UV-FJU-200 have larger pore sizes,and the dihedral angles of the H_(2)L^(2-)in framework has been changed.展开更多
Graphene nanosheets are widely used in anti-corrosion polymeric coating as filler,owing to the excellent electrochemical inertness and barrier property.However,as the arrangement of graphene nanosheets is difficult to...Graphene nanosheets are widely used in anti-corrosion polymeric coating as filler,owing to the excellent electrochemical inertness and barrier property.However,as the arrangement of graphene nanosheets is difficult to form a perfect layered structure,polymeric coating with graphene nanosheets usually needs micron-scale thickness to ensure the enhancement of corrosion protection.In this work,layer-by-layer stacked graphene nanocoatings were fabricated on stainless steel by self-assembly based on Marangoni effect.The anti-corrosion property of graphene coatings were studied through Tafel polarization curves,electrochemical impedance spectroscopy and accelerated corrosion test with extra applied voltage.The self corrosion current density of optimized three-layered graphene coated sample was one quarter of that of bare stainless steel.And the self corrosion potential of optimized sample is increased to-0.045 V.According to the results,graphene nanocoatings composed of layered nanosheets exhibits good anticorrosion property.Besides,the self-assembly method provide a promising approach to make layeredstructure coating for other researches about 2 D material nanosheets.展开更多
The realization of good aqueous dispersibility of commercial graphene products composed of exfoliated graphene sheets is of significance for downstream applications.However,the tap density of commercial graphene powde...The realization of good aqueous dispersibility of commercial graphene products composed of exfoliated graphene sheets is of significance for downstream applications.However,the tap density of commercial graphene powder is quite low(0.03-0.1 kg/m3),meaning that 1 kg graphene powder occupies about 10-30 m3 in volume during transportation.And,the available content of commercial graphene dispersion/slurry in aqueous medium cannot exceed 5 wt%,although the density is high(≈1050 kg/m3).In this work,a graphene monolith was prepared by oven-drying of graphene sheets prefunctionalized with poloxamer surfactants.Our graphene monoliths not only have a high density(1500 kg/m^3) and high graphene content(≈10 wt%),but also a full capability to be completely redispersed(≈100%) in water by bath sonication to obtain solubilized graphene sheets,whose lateral size and thickness are unchanged compared to as-exfoliated ones.Moreover,a simple empirical method was proposed to predict the redispersion capability of graphene monoliths using different poloxamers by contact angle measurements.Our results provide a universal approach to make exfoliated graphene-based products with better downstream availability and lower transportation cost.展开更多
With the explosive development in integration of electronic components and the increasing complexity of packaging systems,semiconductor chips own extremely high operation temperatures given by the horrible heat accumu...With the explosive development in integration of electronic components and the increasing complexity of packaging systems,semiconductor chips own extremely high operation temperatures given by the horrible heat accumulation attributed to the drastically increasing power density. Therefore, highly efficient heat dissipation with the help of rationally designed thermal interface materials(TIMs) is the key to maintaining the device performance and lifespan. Graphene exhibits an ultrahigh intrinsic thermal conductivity, which has attracted a large amount of academic interest due to its significant potential for developing high-performance TIMs. In this tutorial review, we summarize the recent advances in graphene-based TIMs, especially emphasizing the determinate effects of graphene structure and alignment in enhancing the heat transfer capacity of corresponding samples,with detailed discussion in the superiorities and limitations of various graphene skeletons. In addition, we also provide prospects for the challenges and opportunities in the future development of graphene-based TIMs.展开更多
基金flnancial support by the National Natural Science Foundation of China (52102055, 5227020331, 52075527)National Key R&D Program of China (2017YFB0406000 and 2017YFE0128600)+8 种基金the Project of the Chinese Academy of Sciences (XDC07030100, XDA22020602, ZDKYYQ20200001 and ZDRW-CN-2019-3)CAS Youth Innovation Promotion Association (2020301)Science and Technology Major Project of Ningbo (2021Z120, 2021Z115, 2022Z084, 2018B10046 and 2016S1002)the Natural Science Foundation of Ningbo (2017A610010)Foundation of State Key Laboratory of Solid lubrication (LSL-1912)China Postdoctoral Science Foundation (2020M681965, 2022M713243)National Key Laboratory of Science and Technology on Advanced Composites in Special Environments (6142905192806)K.C. Wong Education Foundation (GJTD-2019-13)the 3315 Program of Ningbo for financial support
文摘Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of high-power semiconductor devices.Based on the ultra-high basal-plane thermal conductivity,graphene is an ideal candidate for preparing high-performance TIMs,preferably to form a vertically aligned structure so that the basal-plane of graphene is consistent with the heat transfer direction of TIM.However,the actual interfacial heat transfer efficiency of currently reported vertically aligned graphene TIMs is far from satisfactory.In addition to the fact that the thermal conductivity of the vertically aligned TIMs can be further improved,another critical factor is the limited actual contact area leading to relatively high contact thermal resistance(20-30 K mm^(2) W^(−1))of the“solid-solid”mating interface formed by the vertical graphene and the rough chip/heat sink.To solve this common problem faced by vertically aligned graphene,in this work,we combined mechanical orientation and surface modification strategy to construct a three-tiered TIM composed of mainly vertically aligned graphene in the middle and micrometer-thick liquid metal as a cap layer on upper and lower surfaces.Based on rational graphene orientation regulation in the middle tier,the resultant graphene-based TIM exhibited an ultra-high thermal conductivity of 176 W m^(−1) K^(−1).Additionally,we demonstrated that the liquid metal cap layer in contact with the chip/heat sink forms a“liquid-solid”mating interface,significantly increasing the effective heat transfer area and giving a low contact thermal con-ductivity of 4-6 K mm^(2) W^(−1) under packaging conditions.This finding provides valuable guidance for the design of high-performance TIMs based on two-dimensional materials and improves the possibility of their practical application in electronic thermal management.
基金supported by the CAS President’s International Fellowship Initiative (2016PT028)the National Natural Science Foundation of China (21273225 and 21403219)~~
基金National Natural Science Foundation of China (Grant Nos 30470074,30671615)Innovation Project of the Chinese Academy of Sciences (KSCX2-YW-N-021).
文摘Grass carp reovirus(GCRV),a disaster agent to aquatic animals,belongs to Genus Aquareovirus of family Reoviridea.Sequence analysis revealed GCRV genome segment 8(s8) was 1 296 bp nucleotides in length encoding an inner capsid protein VP6 of about 43kDa.To obtain in vitro non-fusion expression of a GCRV VP6 protein containing a molecular of fluorescence reporter,the recombinant baculovirus,which contained the GCRVs8 and eGFP(enhanced green fluorescence protein) genes,was constructed by using the Bac-to-Bac insect expression system.In this study,the whole GCRVs8 and eGFP genes,amplified by PCR,were constructed into a pFastBacDual vector under polyhedron(PH) and p10 promoters,respectively.The constructed dual recombinant plasmid(pFbDGCRVs8/eGFP) was transformed into DH10Bac cells to obtain recombinant Bacmid(AcGCRVs8/eGFP) by transposition.Finally,the recombinant bacluovirus(vAcGCRVs8/eGFP) was obtained from transfected Sf9 insect cells.The green fluorescence that was expressed by transfected Sf9 cells was initially observed 3 days post transfection,and gradually enhanced and extended around 5 days culture in P1(Passage1) stock.The stable high level expression of recombinant protein was observed in P2 and subsequent passage budding virus(BV) stock.Additionally,PCR amplification from P1 and amplified P2 BV stock further confirmed the validity of the dual-recombinant baculovirus.Our results provide a foundation for expression and assembly of the GCRV structural protein in vitro.
基金Supported by The Hospital-Funded Clinical Research of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine,No.17CSY01.
文摘BACKGROUND Assessment of the vascular status following limb fracture in children is important to evaluate the risk of compartment syndrome,which is an emergency condition.AIM To establish a simple and efficient grading scale of limb perfusion in children undergoing surgery for limb fracture.METHODS This retrospective study included pediatric patients with a limb fracture and postoperative plaster fixation who were admitted at The Department of Pediatric Orthopedics of Xinhua Hospital between February 2017 and August 2017.The outcome was poor limb perfusion,which is defined as the postoperative use of mannitol.The children were divided into two groups:The normal perfusion group and the poor perfusion group.Key risk factors have been selected by univariable analyses to establish the Grading Scale for Vascular Status.RESULTS A total of 161 patients were included in the study:85 in the normal perfusion group and 76 in the poor perfusion group.There were no significant differences in age,sex,body mass index,ethnicity,cause of fracture,fixation,or site of fracture between the two groups.After surgery,the skin temperature(P=0.048)and skin color(P<0.001)of the affected limb were significantly different between the two groups.The relative risk and 95%confidence interval for skin temperature of the affected limb,skin color,and range of motion of the affected limb are 2.18(1.84-2.59),2.89(2.28-3.66),and 2.16(1.83-2.56),respectively.The grading scale was established based on those three factors(score range:0-3 points).Forty-one patients(32.5%)with score 0 had poor limb perfusion;all patients with scores 1(n=32)and 2(n=3)had poor limb perfusion(both 100%).CONCLUSION In children undergoing surgery for limb fracture,a higher Grading Scale for Vascular Status score is associated with a higher occurrence of poor limb perfusion.A prospective study is required for validation.
基金financially supported by the National Natural Science Foundation of China (Nos.52075527,5227020331 and 52102055)the National Key R&D Program of China (Nos.2017YFB0406000 and 2017YFE0128600)+12 种基金the Project of the Chinese Academy of Sciences (Nos.XDC07030100,XDA22020602,ZDKYYQ20200001 and ZDRW-CN-2019-3)CAS Youth Innovation Promotion Association (No.2020301)the Science and Technology Major Project of Ningbo (Nos.2021Z115,2021Z120,2018B10046 and 2016S1002)the Key Research and Development Program of Ningbo City (No.2022Z084)the Natural Science Foundation of Ningbo (No.2017A610010)the Foundation of State Key Laboratory of Solid lubrication (No.LSL-1912)China Postdoctoral Science Foundation (Nos.2020M681965 and2022M713243)the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments (No.6142905192806)K.C.Wong Education Foundation (No.GJTD-2019-13)the Youth Fund of Chinese Academy of Sciences (No.JCPYJJ-22030)the Science and Technology Project of Zhejiang Province (No.2022C01182)Zhejiang Provincial Natural Science Foundation of China (No.LY19B010003)the 3315 Program of Ningbo。
文摘With the fast development of integrated circuit devices as well as batteries with high energy densities,the thermal management of electronic components is becoming increasingly crucial to maintaining their reliable operations.Boron nitride nanosheets(BNNS),which have superhigh thermal conductivity along the in-plane direction while remaining electrically insulating,were widely regarded as an ideal filler for preparing high-performance polymer composites to address the‘‘thermal failure''issue.However,due to the instinctive rigidity of BNNS,the nanosheets are unable to form a tightly interfacial contact between the adjoining fillers,resulting in some micro-and nanovoids within the heat transfer pathways and severely limiting further thermal conductivity enhancement for BNNS-based composites.Herein,soft and deformable liquid metal(eutectic gallium-indium,EGaIn)nanoparticles were employed to fill the gaps between the adjacent BNNS with a rational design of mass ratios of BNNS and EGaIn,leading to a strongly synergistic effect with BNNS on thermal conductivity improvement.As a result,the composite film(BNNS:63 wt%and EGaIn:7 wt%)employing cellulose nanofibers(CNF:30 wt%)as the polymer matrix achieves superhigh thermal conductivity along the in-plane direction of up to(90.51±6.71)W·m^(-1)·K^(-1),showing the highest value among the BNNSbased composites with a bi-filler system as far as we know.Additionally,the film can work as a heat spreader for the heat dissipation of high-power light emitting diodes,outperforming tin foil in cooling efficiency.
文摘Epidemiological studies have shown a high prevalence of low serum testosterone levels in men with cardiovascular disease. Moreover, the tyrosine kinase receptor Axl, the ligand of which is growth arrest-specific protein 6 (GAS6), is expressed in the vasculature, and serum GAS6 levels are associated with endothelial dysfunction and cardiovascular events. Testosterone regulates GAS6 gene transcription directly, which inhibits calcification of vascular smooth muscle cells and provides a mechanistic insight into the cardioprotective action of androgens. This study was designed to determine the correlation between serum GAS6 and testosterone levels in male patients with coronary heart disease (CHD). We recruited 225 patients with CHD and 102 apparently healthy controls, Serum concentrations of GAS6 and soluble Axl were quantified by an enzyme-linked immunosorbent assay. Levels of high-sensitivity C-reactive protein, testosterone, estradiol, and other routine biochemical markers were also measured. Testosterone decreased from 432.69 ± 14.40 to 300.76± 6.23 ng d1-1 (P 〈 0.001) and GAS6 decreased from 16.20± 0.31 to 12.51 ± 0.19 ng ml-1 (P 〈 0.001) in patients with CHD, compared with control subjects. Multiple linear regression analysis showed that serum testosterone and GAS6 levels were positively associated in male patients with CHD. Alterations in GAS6 levels may influence the development of CHD. Downregulation of GAS6/Axl signaling in the presence of low sex hormone levels during disease progression is a potential mechanism by which GAS6 affects CHD. This study provides novel results regarding the influence of sex hormones on serum GAS6 levels in patients with CHD.
基金The authors are grateful for the financial support by the National Natural Science Foundation of China(No.52102055)China Postdoctoral Science Foundation(No.2020M681965)+6 种基金Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2019-3)the Project of the Chinese Academy of Sciences(Nos.XDC07030100,XDA22020602,KFZD-SW-409 and ZDKYYQ20200001)CAS Youth Innovation Promotion Association(No.2020301),Science and Technology Major Project of Ningbo(Nos.2018B10046 and 2016S1002)the Natural Science Foundation of Ningbo(No.2017A610010)Foundation of State Key Laboratory of Solid lubrication(No.LSL-1912)National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(No.6142905192806)the K.C.Wong Education Foundation(No.GJTD-2019-13)。
文摘The integration and miniaturization of chips lead to inevitable overheating and increasing electromagnetic interference (EMI) problems, which threaten the performance, stability, and lifetime of electroniccomponents. Therefore, it is important to improve the heat dissipation and EMI shielding performancein device packaging for the steady operation of electronic products. In recent years, due to its intrinsic superior thermal conductivity, proper electrical conductivity, light-weight, and structural adjustability,graphene has been widely used as high thermal and conductive fillers incorporated in the polymer matrix to improve the thermal conductivity and electrical conductivity of composites. This review concludesthe recent development of graphene/polymer composites by using graphene as fillers to improve thethermal conductivity and EMI shielding effectiveness (EMI SE). The structure of graphene embedded inthe composites varies from zero-dimension (0D), one-dimension (1D) to two-dimensions (2D). Moreover,highly thermally and electrically conductive fillers with different dimensions were also modified on thegraphene to improve the composite performance. Finally, this review also makes prospects for the development trend of graphene/polymer composites with high thermal conductivity and EMI SE in the future.
基金financial support by the National Key R&D Program of China (No.2017YFB0406000)Scientific Instrument Developing Project of the Chinese Academy of Sciences (No.YZ201640)+6 种基金the Project of the Chinese Academy of Sciences (No.KFZD-SW-409)Science and Technology Major Project of Ningbo (Nos.2016S1002 and 2016B10038)International S&T Cooperation Program of Ningbo (No. 2017D10016) for financial supportthe Chinese Academy of Sciences for Hundred Talents ProgramChinese Central Government for Thousand Young Talents Program3315 Program of Ningbothe Key Technology of Nuclear Energy (CAS Interdisciplinary Innovation Team,2014)
文摘With the rapid growth in electronic device performance,there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue,thus contributing to the great importance to develop the graphene framework,which is evaluated as the most promising reinforcements for enhancing the thermal conductivity of polymer.Vacuum filtration is a common method to fabricate graphene framework,whereas,it is available to prepare a framework with centimeter-scale thickness by filtrating the graphene-water dispersion,due to the fact of sample cracking caused by the mismatch of surface tension between graphene and water.In this work,a surfactantassisted strategy was proposed by adjusting the surface tension of the water close to that of graphene first,then performing a conventional filtration process,to fabricate graphene framework.As a result,a thick graphene framework(thickness:3 cm)was successfully prepared,and after embedding into epoxy,the framework endows the composite(13.6 wt%)with a high in-plane thermal conductivities of12.4 W/mK,which is equivalent to≈64 times higher than that of neat epoxy.Our method is simple and compatible with the conventional filtration process,suggesting great potential for the mass-production of graphene framework to meet the practical application requirements.
基金The authors are grateful for the financial support by the National Natural Science Foundation of China(51573201 and 51303034)Public Welfare Project of Zhejiang Province(2016C31026)International S&T Cooperation Program of Ningbo(2015D10003)。
文摘Electronic packaging materials and thermal interface materials(TIMs)are widely used in thermal management.In this study,the epoxy composites with core-shell structure SiC@SiO_(2) nanowires(SiC@SiO_(2) NWs)as fillers could effectively enhance the thermal conductivity of epoxy composites.The unique structure of fillers results in a high thermal conductivity of epoxy composites,which is attributed to good interfacial compatibility epoxy matrix and bridging connections of SiC@SiO_(2) NWs.From neat epoxy to 2.5 wt%loading of SiC@SiO_(2) NWs,the thermal conductivity is significantly increased from 0.218 to 0.391 W m^(−1) K^(−1),increased by 79.4%.In addition,the composite with 2.5 wt%filler possess lower coefficient of thermal expansion and better thermal stability than that of neat epoxy.All these outstanding properties imply that epoxy/SiC@SiO_(2) NWs composites could be the ideal candidate for TIM.
基金the National Natural Science Foundation of China(U1709205,52102055)the National Key R&D Program of China(2017YFE0128600)+7 种基金China Postdoctoral Science Foundation(2020M681965)the Project of the Chinese Academy of Sciences(XDC07030100,XDA22020602,KFZD-SW-409,ZDKYYQ20200001,and ZDRW-CN-2019-3)CAS Youth Innovation Promotion Association(2020301)Science and Technology Major Project of Ningbo(2018B10046)the Natural Science Foundation of Ningbo(2017A610010)Foundation of State Key Laboratory of Solid lubrication(LSL-1912)National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(6142905192806)K.C.Wong Education Foundation(GJTD-2019-13).
文摘As the power density of electronic devices increases,there has been an urgent demand to develop highly conductive polymer composites to address the accompanying thermal management issues.Due to the ultra-high intrinsic thermal conductivity,graphene is considered a very promising filler to improve the thermal conductivity of polymers.However,graphene-based polymer composites prepared by the conventional mixing method generally have limited thermal conductivity,even under high graphene loading,due to the failure to construct efficient heat transfer pathways in the polymer matrix.Here,a spiral graphene framework(SGF)containing continuous and highly ordered graphene microtubes was developed based on a modified CVD method.After embedding into the epoxy(EP)matrix,the graphene microtubes can act as efficient heat pathways,endowing the SGF/EP composites with a high through-plane thermal conductivity of 1.35 W·m^(-1)·K^(-1) at an ultralow graphene loading of 0.86 wt%.This result gives a thermal conductivity enhancement per 1 wt%filler loading of 710%,significantly outperforming various graphene structures as fillers.In addition,we demonstrated the practical application of the SGF/EP composite as a thermal interface material for efficient thermal man-agement of the light-emitting diode(LED).
基金supported by the National Natural Science Foundation of China(Nos.21673039,21573042,21805039,21975044,21971038 and 21922810)the Fujian Provincial Department of Science and Technology(Nos.2018J07001 and2019H6012)。
文摘A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection,and the detection limit of aniline can reach5.5 x 10^(-4)mol/L.Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown,which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection.Moreover,for more convenient use,FJU-200 test papers are prepared.Using them,convenient and fast aniline or ultraviolet detection can be realized.The single-crystal X-ray structures show that compared with the original FJU-200,both PhNH_(2)@FJU-200 and UV-FJU-200 have larger pore sizes,and the dihedral angles of the H_(2)L^(2-)in framework has been changed.
基金the financial support by the National Natural Science Foundation of China(Nos.51573201,51501209,201675165 and 61901460)NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(No.U1709205)+7 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22000000)Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YZ201640)Science and Technology Major Project of Ningbo(Nos.2016S1002 and 2016B10038)International S&T Cooperation Program of Ningbo(No.2017D10016)China Postdoctoral Science Foundation(No.2019M653125)for financial supportthe Chinese Academy of Sciences for Hundred Talents ProgramChinese Central Government for Thousand Young Talents Program3315 Program of Ningbo。
文摘Graphene nanosheets are widely used in anti-corrosion polymeric coating as filler,owing to the excellent electrochemical inertness and barrier property.However,as the arrangement of graphene nanosheets is difficult to form a perfect layered structure,polymeric coating with graphene nanosheets usually needs micron-scale thickness to ensure the enhancement of corrosion protection.In this work,layer-by-layer stacked graphene nanocoatings were fabricated on stainless steel by self-assembly based on Marangoni effect.The anti-corrosion property of graphene coatings were studied through Tafel polarization curves,electrochemical impedance spectroscopy and accelerated corrosion test with extra applied voltage.The self corrosion current density of optimized three-layered graphene coated sample was one quarter of that of bare stainless steel.And the self corrosion potential of optimized sample is increased to-0.045 V.According to the results,graphene nanocoatings composed of layered nanosheets exhibits good anticorrosion property.Besides,the self-assembly method provide a promising approach to make layeredstructure coating for other researches about 2 D material nanosheets.
基金financial support by the National Natural Science Foundation of China(Nos.51573201,51501209 and 201675165)NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(No.U1709205)+6 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22000000)Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YZ201640)Science and Technology Major Project of Ningbo(Nos.2016S1002 and 2016B10038)International S&T Cooperation Program of Ningbo(No.2017D10016)for financial supportthe Chinese Academy of Sciences for Hundred Talents ProgramChinese Central Government for Thousand Young Talents Program3315 Program of Ningbo。
文摘The realization of good aqueous dispersibility of commercial graphene products composed of exfoliated graphene sheets is of significance for downstream applications.However,the tap density of commercial graphene powder is quite low(0.03-0.1 kg/m3),meaning that 1 kg graphene powder occupies about 10-30 m3 in volume during transportation.And,the available content of commercial graphene dispersion/slurry in aqueous medium cannot exceed 5 wt%,although the density is high(≈1050 kg/m3).In this work,a graphene monolith was prepared by oven-drying of graphene sheets prefunctionalized with poloxamer surfactants.Our graphene monoliths not only have a high density(1500 kg/m^3) and high graphene content(≈10 wt%),but also a full capability to be completely redispersed(≈100%) in water by bath sonication to obtain solubilized graphene sheets,whose lateral size and thickness are unchanged compared to as-exfoliated ones.Moreover,a simple empirical method was proposed to predict the redispersion capability of graphene monoliths using different poloxamers by contact angle measurements.Our results provide a universal approach to make exfoliated graphene-based products with better downstream availability and lower transportation cost.
基金supported by the National Natural Science Foundation of China (Grant Nos. 52075527, U1709205, and 52102055)National Key R&D Program of China (Grant Nos. 2017YFB0406000, and 2017YFE0128600)+8 种基金Project of the Chinese Academy of Sciences (Grant Nos. XDC07030100, XDA22020602, ZDKYYQ20200001, and ZDRW-CN-20193)CAS Youth Innovation Promotion Association (Grant No. 2020301)Science and Technology Major Project of Ningbo (Grant Nos. 2021Z120, 2021Z115, 2022Z084, 2018B10046, and 2016S1002)Natural Science Foundation of Ningbo (Grant No. 2017A610010)Foundation of State Key Laboratory of Solid lubrication (Grant No. LSL-1912)China Postdoctoral Science Foundation (Grant Nos. 2020M681965, and 2022M713243)National Key Laboratory of Science and Technology on Advanced Composites in Special Environments (Grant No. 6142905192806)K. C. Wong Education Foundation (Grant No. GJTD-2019-13)3315 Program of Ningbo for financial support。
文摘With the explosive development in integration of electronic components and the increasing complexity of packaging systems,semiconductor chips own extremely high operation temperatures given by the horrible heat accumulation attributed to the drastically increasing power density. Therefore, highly efficient heat dissipation with the help of rationally designed thermal interface materials(TIMs) is the key to maintaining the device performance and lifespan. Graphene exhibits an ultrahigh intrinsic thermal conductivity, which has attracted a large amount of academic interest due to its significant potential for developing high-performance TIMs. In this tutorial review, we summarize the recent advances in graphene-based TIMs, especially emphasizing the determinate effects of graphene structure and alignment in enhancing the heat transfer capacity of corresponding samples,with detailed discussion in the superiorities and limitations of various graphene skeletons. In addition, we also provide prospects for the challenges and opportunities in the future development of graphene-based TIMs.