In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applic...In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.展开更多
Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape o...Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape on particle breakage.A quantitative parameter for the three-dimensional particle shape(Average spherical modulus G_(M))is proposed in this study.Combined with G_(M),the triaxial compression test of granular materials with different particle shapes was carried out,and the particle size distribution before and after the test was determined.The results indicate that the local damage mechanism governs the macroscopic deformation behavior of granular materials,as influenced by the particle gradation of the samples before and after the triaxial compression test.Based on these findings,a binary medium model with a friction element weakening factor is proposed.This model incorporates the effects of particle shape and breakage behavior,significantly enhancing its calculation accuracy.Experimental results demonstrate that the model effectively predicts the deformation of crushable granular materials,accounting for particle shape.展开更多
A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum ...A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum adsorption roller to prepare phase change material(PCM)particle(PCP).Then EP and EVMT-based composite PCM plates were respectively fabricated through a mold pressing method.The thermal property,chemical stability,microstructure and durability were characterized by differential scanning calorimeter(DSC),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM)and thermal cycling tests,respectively.The results show that both PCPs have high latent heats with 110 J/g for EP-based PCP and more than 130 J/g for EVMT-based PCP,compact microstructure without PCM leakage,stable chemical property and good durability.The research results have proved the feasibility for the vacuum adsorption roller used in the composite PCM fabrication.Results of thermal storage performance experiment indicate that the fabricated PCM plates have better thermal inertia than common building materials,and the thermal storage performance of PCM plates has nonlinearly changed with outside air velocity and temperature increase.Therefore,PCM plates show a significant potential for the practical application of building thermal storage.展开更多
The particle size ratio(PSR)is an important parameter for binary granular materials,which may aect the microstructure and macro behaviors of granular materials.However,the eect of particle ratio on granular assembli...The particle size ratio(PSR)is an important parameter for binary granular materials,which may aect the microstructure and macro behaviors of granular materials.However,the eect of particle ratio on granular assemblies with dierent arrangements is still unclear.To explore and further clarify the eect of PSR in dierent packing structures,three types of numerical samples with regular,layered,and random packing are designed.Numerical results show that PSR has signicant eects on binary granular samples with regular packing.The larger the PSR,the stronger the strength,the larger the modulus,and the smaller the angle between the shear band and the load direction.And a theoretical solution of the peak stress ratio vs.PSR is obtained for regular packing,and the results by DEM are in good agreement with the theoretical solution.Under layered packing,PSR has little eect on peak stress ratio due to similar microstructure obtained with the changing of PSR.The modulus slightly increased with the increase of PSR.Under random packing with small grain content of 50%,PSR has little eect in the range of 0.5–0.9,but in a larger range,larger PSR leads to greater modulus.展开更多
The mean sputter depth depends on the surface composition gradient during ion implantation.For the high fluence ion implantation into a Pt-Cu alloy, the surface composition gradient of Cu is so large that the differen...The mean sputter depth depends on the surface composition gradient during ion implantation.For the high fluence ion implantation into a Pt-Cu alloy, the surface composition gradient of Cu is so large that the difference in mean sputter depth between Pt and Cu, is significant. However, for the high fluence ion implantation into 10B-11B isotope mixture, the surface composition gradient of 10B is so small that the difference in mean sputter depth between 10B and 11B is insignificant.展开更多
The thermal energy storage phase change material used for building has been prepared with a few of fatty acids based on the principle of binary low eutectic point. The thermal behaviors such as phase transition temper...The thermal energy storage phase change material used for building has been prepared with a few of fatty acids based on the principle of binary low eutectic point. The thermal behaviors such as phase transition temperature and enthalpy of compound energy storage material are researched through differential scanning calorimeter(DSC) and scanning electron microscope(SEM) . The results show that the thermal energy storage phase change composite material can be used in the wall panels well as its higher latent heat.展开更多
A lightweight composite resonator,consisting of a soft material acoustic black hole(SABH)and multiple vibration absorbers,is embedded in a plate to achieve localization and absorption of low-frequency vibration energy...A lightweight composite resonator,consisting of a soft material acoustic black hole(SABH)and multiple vibration absorbers,is embedded in a plate to achieve localization and absorption of low-frequency vibration energy.The combination of local and global admissible functions for displacement enhances the accuracy of the Ritz method in predicting vibration localization characteristics within the SABH domain.Utilizing soft materials for the SABH can reduce the mass and frequency of the composite resonator.Due to the lack of orthogonality between global vibration modes and localized modes,the low-frequency localized modes induced by the SABH are used to shape the initial global modes,thereby concentrating the global vibration of the plate in the SABH region.Consequently,the absorbers of the composite resonator only need to be a small fraction of the mass of the local SABH to achieve substantial vibration control of the host plate.This vibration localization strategy can significantly reduce the vibration amplitude of the host plate and enhance the effectiveness of lightweight absorbers in vibration reduction.展开更多
How to obtain organic electro-optic materials with large electro-optic coefficients,high glass transition temperature,and good optical transparency remains a challenge in this field.To solve this problem,we introduce ...How to obtain organic electro-optic materials with large electro-optic coefficients,high glass transition temperature,and good optical transparency remains a challenge in this field.To solve this problem,we introduce groups that can undergo Huisgen cycloaddition reactions into the donor and electron bridge of chromophores with large hyperpolarizability using tetrahydroquinoline as the donor.Binary cross-linkable chromophores TLD1-2 with CF_(3)-TCF as the acceptor and chromophores TLD3-4 with 5Fph-TCF as the acceptor were synthesized.After poling and crosslinking,the T_(g)of TLD1/TLD2 and TLD3/TLD4 were raised to 152 and 174°C,respectively.The electro-optical coefficients of chromophores TLD1/TLD2 and TLD3/TLD4 were as high as 312 pm/V and 287 pm/V,respectively.The long-term alignment stability test showed that after being left at 85℃ for 500 h,the cross-linked film TLD3/TLD4 can still maintain more than 98%of the original electro-optical coefficient value,which is higher than that of TLD1/TLD2(93%).The chromophore TLD3-4 exhibited much blue-shifted maximum absorption wavelengths(~40 nm)compared to TLD1-2 which was beneficial for reducing optical loss in the device.The combination of high electro-optic coefficient,strong stability,and excellent optical transparency makes the TLD series of binary cross-linked materials very promising for practical high-performance electro-optic devices.展开更多
For a compact millimeter wave imaging system it is very important to design every component into small size, for the components in a millimeter wave system are usually much larger than those in an optical imaging syst...For a compact millimeter wave imaging system it is very important to design every component into small size, for the components in a millimeter wave system are usually much larger than those in an optical imaging system due to rela-tively long wave lengths. In this paper, we suggest a kind of binary diffractive lens (BDL) designed using double nega-tive materials (DNG) as the objective lens for a millimeter wave imaging system. The DNG-BDL has not only the ad-vantage of low profile but also small f number, which will be benefit for constructing a compact millimeter wave imaging system. Several DNG-BDL are designed and analyzed using the FDTD method. The numerical results of the focal plane field of the DNG-BDL are presented, which show that the DNG-BDL with small f number has relatively better focusing characteristic than that of a double positive BDL with same f number.展开更多
We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we...We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we found small intrinsic variabilities,such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas.By the Wilson-Devinney Code,we deduced six photometric solutions.The dark spot of V523 Cas may appear on the surface of the more massive component on BJD 2458768,while it disappears on BJD 2458779.Our results indicate that the two binaries are W-type shallow-contact binaries(f≤10%).From the eclipse timing residuals,we found that the orbital periods may continuously increase,accompanied by one to two light-time effects due to additional bodies.The modulated periods and semi-amplitudes are P_(3)=25.8(±1.0)yr and A_(3)=0_·^(d)0066(6)for HI Leo,P_(3)=-14.8(±2.0)yr and A_(3)=0_·^(d)0448(12),P_(4)=18.89(±0.14)yr and A4=0_·^(d)0025(2)for V523 Cas,respectively.The orbital period secularly increases at a rate of dP/dt=2.86(±0.11)×10^(-7)day yr^(-1)for HI Leo and dP/dt=3.45(±0.07)×10^(-8)day yr^(-1)for V523 Cas,which may be attributed to mass transfer from the secondary to the primary.With mass transferring,the shallow-contact binaries,HI Leo and V523 Cas,will evolve into the broken-contact configurations.展开更多
针对建筑垃圾物料的种类多、形貌易混淆等问题,构建了一种基于局部约束的视觉词袋(local constraint-bag of visual words,LC-BoVW)模型的建筑垃圾物料识别算法。首先,对建筑垃圾物料图像分块,分别提取局部颜色特征和局部二值模式特征;...针对建筑垃圾物料的种类多、形貌易混淆等问题,构建了一种基于局部约束的视觉词袋(local constraint-bag of visual words,LC-BoVW)模型的建筑垃圾物料识别算法。首先,对建筑垃圾物料图像分块,分别提取局部颜色特征和局部二值模式特征;考虑到图像分块特征的局部相似特性,构建LC-BoVW模型分别对目标图像的显著特征进行统计。然后,基于信息融合思想对特征统计量进行融合,形成图像的判别性特征并输入到分类器中进行物料的精确识别。最后,利用自建的5类建筑垃圾物料图像数据集进行实验,实验结果表明,所提算法能够快速有效地实现建筑垃圾物料识别,平均识别准确率可达到97.92%。展开更多
基金supported by the National Key R&D Program(Grant No.2022YFA1203-100)sponsorship by Shanghai Sailing Program(Grant No.24YF2713800)+2 种基金financial support from the Local College Capacity Building Project of Shanghai Municipal Science and Technology Commission(Grant No.20010500700)the Natural Science Foundation of Shanghai(Grant No.23ZR1424300)Shanghai Shuguang Program(Grant No.22SG56)。
文摘In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.
基金the National Natural Science Foundation of China(Grant No.12372376)the Scientific Innovation Practice Project of Postgraduates of Chang’an University(300103724017)。
文摘Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape on particle breakage.A quantitative parameter for the three-dimensional particle shape(Average spherical modulus G_(M))is proposed in this study.Combined with G_(M),the triaxial compression test of granular materials with different particle shapes was carried out,and the particle size distribution before and after the test was determined.The results indicate that the local damage mechanism governs the macroscopic deformation behavior of granular materials,as influenced by the particle gradation of the samples before and after the triaxial compression test.Based on these findings,a binary medium model with a friction element weakening factor is proposed.This model incorporates the effects of particle shape and breakage behavior,significantly enhancing its calculation accuracy.Experimental results demonstrate that the model effectively predicts the deformation of crushable granular materials,accounting for particle shape.
基金Project(51408184)supported by the National Natural Science Foundation of ChinaProject(E2017202136)supported by the Natural Science Foundation of Hebei Province,China+1 种基金Project(BSBE2017-05)supported by Opening Funds of State Key Laboratory of Building Safety and Built Environment and National Engineering Research Center of Building Technology,ChinaProject(QG2018-3)supported by Hebei Provincial Department of Transportation,China
文摘A binary eutectic mixture composed of tetradecanol(TD)and myristic acid(MA)was maximally absorbed into the microstructures of expanded perlite(EP)and expanded vermiculite(EVMT),respectively,through a self-made vacuum adsorption roller to prepare phase change material(PCM)particle(PCP).Then EP and EVMT-based composite PCM plates were respectively fabricated through a mold pressing method.The thermal property,chemical stability,microstructure and durability were characterized by differential scanning calorimeter(DSC),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM)and thermal cycling tests,respectively.The results show that both PCPs have high latent heats with 110 J/g for EP-based PCP and more than 130 J/g for EVMT-based PCP,compact microstructure without PCM leakage,stable chemical property and good durability.The research results have proved the feasibility for the vacuum adsorption roller used in the composite PCM fabrication.Results of thermal storage performance experiment indicate that the fabricated PCM plates have better thermal inertia than common building materials,and the thermal storage performance of PCM plates has nonlinearly changed with outside air velocity and temperature increase.Therefore,PCM plates show a significant potential for the practical application of building thermal storage.
基金supported by the National Natural Science Foundation of China (Nos.12172263,11772237).
文摘The particle size ratio(PSR)is an important parameter for binary granular materials,which may aect the microstructure and macro behaviors of granular materials.However,the eect of particle ratio on granular assemblies with dierent arrangements is still unclear.To explore and further clarify the eect of PSR in dierent packing structures,three types of numerical samples with regular,layered,and random packing are designed.Numerical results show that PSR has signicant eects on binary granular samples with regular packing.The larger the PSR,the stronger the strength,the larger the modulus,and the smaller the angle between the shear band and the load direction.And a theoretical solution of the peak stress ratio vs.PSR is obtained for regular packing,and the results by DEM are in good agreement with the theoretical solution.Under layered packing,PSR has little eect on peak stress ratio due to similar microstructure obtained with the changing of PSR.The modulus slightly increased with the increase of PSR.Under random packing with small grain content of 50%,PSR has little eect in the range of 0.5–0.9,but in a larger range,larger PSR leads to greater modulus.
文摘The mean sputter depth depends on the surface composition gradient during ion implantation.For the high fluence ion implantation into a Pt-Cu alloy, the surface composition gradient of Cu is so large that the difference in mean sputter depth between Pt and Cu, is significant. However, for the high fluence ion implantation into 10B-11B isotope mixture, the surface composition gradient of 10B is so small that the difference in mean sputter depth between 10B and 11B is insignificant.
基金the National Support Projects of the Eleventh Five-year Plan (No. 2006BAJ02B01)the Special Research Projects of Shaanxi Province Education Department (No. 08JK316)the Key Discipline Construction Projects of Shaanxi Province for Funding Support
文摘The thermal energy storage phase change material used for building has been prepared with a few of fatty acids based on the principle of binary low eutectic point. The thermal behaviors such as phase transition temperature and enthalpy of compound energy storage material are researched through differential scanning calorimeter(DSC) and scanning electron microscope(SEM) . The results show that the thermal energy storage phase change composite material can be used in the wall panels well as its higher latent heat.
基金supported by the National Natural Science Foundation of China(Grant Nos.12302006,12132002,and 62188101).
文摘A lightweight composite resonator,consisting of a soft material acoustic black hole(SABH)and multiple vibration absorbers,is embedded in a plate to achieve localization and absorption of low-frequency vibration energy.The combination of local and global admissible functions for displacement enhances the accuracy of the Ritz method in predicting vibration localization characteristics within the SABH domain.Utilizing soft materials for the SABH can reduce the mass and frequency of the composite resonator.Due to the lack of orthogonality between global vibration modes and localized modes,the low-frequency localized modes induced by the SABH are used to shape the initial global modes,thereby concentrating the global vibration of the plate in the SABH region.Consequently,the absorbers of the composite resonator only need to be a small fraction of the mass of the local SABH to achieve substantial vibration control of the host plate.This vibration localization strategy can significantly reduce the vibration amplitude of the host plate and enhance the effectiveness of lightweight absorbers in vibration reduction.
基金supported by the Guangzhou Municipal Science and Technology Project(No.202102010426)the National Natural Science Foundation of China(Nos.21805049 and 22074025)Engineering Research Centre of Photonic Design Software,Ministry of Education,China(No.62175267).
文摘How to obtain organic electro-optic materials with large electro-optic coefficients,high glass transition temperature,and good optical transparency remains a challenge in this field.To solve this problem,we introduce groups that can undergo Huisgen cycloaddition reactions into the donor and electron bridge of chromophores with large hyperpolarizability using tetrahydroquinoline as the donor.Binary cross-linkable chromophores TLD1-2 with CF_(3)-TCF as the acceptor and chromophores TLD3-4 with 5Fph-TCF as the acceptor were synthesized.After poling and crosslinking,the T_(g)of TLD1/TLD2 and TLD3/TLD4 were raised to 152 and 174°C,respectively.The electro-optical coefficients of chromophores TLD1/TLD2 and TLD3/TLD4 were as high as 312 pm/V and 287 pm/V,respectively.The long-term alignment stability test showed that after being left at 85℃ for 500 h,the cross-linked film TLD3/TLD4 can still maintain more than 98%of the original electro-optical coefficient value,which is higher than that of TLD1/TLD2(93%).The chromophore TLD3-4 exhibited much blue-shifted maximum absorption wavelengths(~40 nm)compared to TLD1-2 which was beneficial for reducing optical loss in the device.The combination of high electro-optic coefficient,strong stability,and excellent optical transparency makes the TLD series of binary cross-linked materials very promising for practical high-performance electro-optic devices.
文摘For a compact millimeter wave imaging system it is very important to design every component into small size, for the components in a millimeter wave system are usually much larger than those in an optical imaging system due to rela-tively long wave lengths. In this paper, we suggest a kind of binary diffractive lens (BDL) designed using double nega-tive materials (DNG) as the objective lens for a millimeter wave imaging system. The DNG-BDL has not only the ad-vantage of low profile but also small f number, which will be benefit for constructing a compact millimeter wave imaging system. Several DNG-BDL are designed and analyzed using the FDTD method. The numerical results of the focal plane field of the DNG-BDL are presented, which show that the DNG-BDL with small f number has relatively better focusing characteristic than that of a double positive BDL with same f number.
基金supported by the National Natural Science Foundation of China(Grant No.11873003)。
文摘We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we found small intrinsic variabilities,such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas.By the Wilson-Devinney Code,we deduced six photometric solutions.The dark spot of V523 Cas may appear on the surface of the more massive component on BJD 2458768,while it disappears on BJD 2458779.Our results indicate that the two binaries are W-type shallow-contact binaries(f≤10%).From the eclipse timing residuals,we found that the orbital periods may continuously increase,accompanied by one to two light-time effects due to additional bodies.The modulated periods and semi-amplitudes are P_(3)=25.8(±1.0)yr and A_(3)=0_·^(d)0066(6)for HI Leo,P_(3)=-14.8(±2.0)yr and A_(3)=0_·^(d)0448(12),P_(4)=18.89(±0.14)yr and A4=0_·^(d)0025(2)for V523 Cas,respectively.The orbital period secularly increases at a rate of dP/dt=2.86(±0.11)×10^(-7)day yr^(-1)for HI Leo and dP/dt=3.45(±0.07)×10^(-8)day yr^(-1)for V523 Cas,which may be attributed to mass transfer from the secondary to the primary.With mass transferring,the shallow-contact binaries,HI Leo and V523 Cas,will evolve into the broken-contact configurations.
文摘针对建筑垃圾物料的种类多、形貌易混淆等问题,构建了一种基于局部约束的视觉词袋(local constraint-bag of visual words,LC-BoVW)模型的建筑垃圾物料识别算法。首先,对建筑垃圾物料图像分块,分别提取局部颜色特征和局部二值模式特征;考虑到图像分块特征的局部相似特性,构建LC-BoVW模型分别对目标图像的显著特征进行统计。然后,基于信息融合思想对特征统计量进行融合,形成图像的判别性特征并输入到分类器中进行物料的精确识别。最后,利用自建的5类建筑垃圾物料图像数据集进行实验,实验结果表明,所提算法能够快速有效地实现建筑垃圾物料识别,平均识别准确率可达到97.92%。
