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测量材料压力依赖性粘度的专利技术有助于更准确地预测翘曲行为

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橡胶参考资料 2018年第4期48卷 35-36页

作者：王文博

在成型超薄壁塑料零件时,需要高注射速度确保完整填充型腔。当然,高注射速度会导致高填充压力,这会导致聚合物链自由体积的压缩。因此,粘度将会增高,流动阻力会增大。保压过程中,熔体处于高压力和低剪切速率条件下,因此,压力对粘度的影... 详细信息

在成型超薄壁塑料零件时,需要高注射速度确保完整填充型腔。当然,高注射速度会导致高填充压力,这会导致聚合物链自由体积的压缩。因此,粘度将会增高,流动阻力会增大。保压过程中,熔体处于高压力和低剪切速率条件下,因此,压力对粘度的影响将变得更重要。在这些情况下,压力分布会影响局部粘度,从而会影响保压压力分布。

关键词：压力依赖性粘度专利技术行为翘曲预测材料测量

高频电场与正应力场协同作用下聚合物的热响应特性

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华南理工大学学报（自然科学版） 2018年第2期46卷 131-139页

作者：杨智韬童益彰徐文华殷小春张桂珍瞿金平华南理工大学聚合物新型成型装备国家工程研究中心∥聚合物成型加工工程教育部重点实验室广东广州510640

目前高分子材料成型方法都采用高温塑化、低温成型的成型机理进行加工.这一过程消耗了大量的能量,并造成聚合物及其添加剂的热降解,降低了塑料的性能和可回收性.因此,文中在聚合物热压成型加工中引入高频电场,使物料在正应力和高频电场... 详细信息

目前高分子材料成型方法都采用高温塑化、低温成型的成型机理进行加工.这一过程消耗了大量的能量,并造成聚合物及其添加剂的热降解,降低了塑料的性能和可回收性.因此,文中在聚合物热压成型加工中引入高频电场,使物料在正应力和高频电场协同作用下实现低温塑化,研究物料在高频电场中发生热响应的压力、温度依赖性,以及在临界塑化温度点下制备的聚合物片材的力学性能,建立合理的温升模型.研究表明:材料极性越强,其介电损耗越高,物料吸热能力越强;极性材料和非结晶性聚合物吸热量随成型压力的增大而增大,而非极性的结晶性聚合物吸热量存在最佳吸热压力点;均聚物具有最佳吸热温度点,而多相的共聚物吸热量随加工温度呈指数增长;施加高频电场试样的拉伸性能显著提升,证实了协同低温塑化行为的存在.

关键词：高频电场正应力温升模型压力依赖性温度依赖性低温塑化

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估算饱和岩石裂隙结构参数的模型研究

中外能源 2023年第9期28卷 49-55页

作者：吴春芳上海电子信息职业技术学院上海201411

从弹性波速对压力依赖性的关系可以反演岩石裂隙参数分布。然而在超声波频率段,Gassmann方程不能有效解释压力梯度的非驰豫现象。为了从饱和岩石波速得到裂隙结构参数,构建双孔(裂隙与孔隙)结构岩石骨架模型,获取裂隙结构参数与有效压... 详细信息

从弹性波速对压力依赖性的关系可以反演岩石裂隙参数分布。然而在超声波频率段,Gassmann方程不能有效解释压力梯度的非驰豫现象。为了从饱和岩石波速得到裂隙结构参数,构建双孔(裂隙与孔隙)结构岩石骨架模型,获取裂隙结构参数与有效压力的关系。利用Gurevich关系式解释高频条件下压力梯度的非驰豫现象,形成岩石骨架在高频饱和状态下的弹性特征。结合岩石骨架模型,通过饱和岩石弹性波速度对裂隙结构参数进行估算,形成一种不同压力下估算饱和岩石裂隙结构参数的计算模型。基于该模型可分别得到裂隙密度与有效压力预测曲线及裂隙孔隙度与有效压力预测曲线。三块岩石样本的超声波实验数据表明,该估算模型能有效地描述岩石弹性特征的压力依赖性。采用高压状态下的岩石来近似代替仅含硬孔隙的岩石主相并不精确,且裂隙-硬孔隙间存在一定的相互关系。

关键词：双孔结构裂隙结构参数有效压力弹性波速度压力依赖性

Ab initio Predictions of Structural and Thermodynamic Properties of Zr2AIC Under High Pressure and High Temperature

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Chinese Journal of Chemical Physics 2015年第3期28卷 263-268,I0001页

作者： Fen Luo Zhi-cheng Guo Xiu-lu Zhang Chang-ying Yuan Ling-cang Cai Laboratory for Extreme Conditions Matter Properties Southwest University of Science and Technol- ogy Mianyang 521900 China National Key Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics Chinese Academy of Engineering Physics Mianyang 521900 China

The structural and thermodynamic properties of Zr2AlC at high pressure and high temperature are investigated by first principles density functional theory method. The calculated lattice parameters of Zr2AlC are in good agreement with the available theoretical data. The pressure dependences of the elastic constants, bulk modulus, shear modulus, Young's modulus, and Vickers hardness of Zr2AlC are successfully obtained. The elastic anisotropy is examined through the computation of the direction dependence of Young's modulus. By using the quasiharmonic Debye model, the thermodynamic properties including the Debye temperature, heat capacity, volume thermal expansion coefficient, and Grüneisen parameter at high pressure and temperature are predicted for the first time.

关键词：热力学性质高温高压从头预测结构压力依赖性密度泛函理论弹性各向异性回火温度

A first-principles study of the structural,electronic and elastic properties of solid nitromethane under pressure

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Science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1874-1881页

作者： CHANG Jing ZHOU XiaoLin ZHAO GuoPing WANG Li College of Physics and Electronic Engineering Sichuan Normal University

The structural,electronic and elastic properties of solid nitromethane are investigated under pressure by performing first-principles density functional theory(DFT)calculations within the generalized gradient approximation(GGA)and the local density approximation(LDA).The obtained ground state structure properties are found to be consistent with existing experimental and theoretical results.The pressure-induced variations of structure parameters(a,b,c and V)indicate that the solid nitromethane has an anisotropic compressibility,and the compression along the c direction is more difficult than along a and b directions.From the vibration curves of intermolecular bond length and bond angle,we find that the C—N bond is the most sensitive among these bonds under pressure,suggesting that the C—N bonds may be broken first under external loading.The influence of pressure on the electronic properties of solid NM has been studied,indicating that solid NM is an insulating compound with a large indirect band gap and tends to be a semiconductor with increasing pressure.Finally,we predict the elastic constants and their pressure dependence for the solid NM with the bulk modulus,Young’s modulus,shear modulus and the Poisson’s ratio derived.

关键词：压力依赖性硝基甲烷第一原理弹性性质电子结构固体密度泛函理论广义梯度近似

Controlling Thermal Conductivity of Few-Layer Graphene Nanoribbons by Using the Transversal Pressure

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Communications in Theoretical Physics 2013年第9期60卷 353-356页

作者：钟伟荣杨明明张茂平艾保全 Department of Physics and Siyuan Laboratory College of Science and EngineeringJinan University Laboratory of Quantum Information Technology ICMP and SPTESouth China Normal University

We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations.It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons.This improvement can reach 37.5%in the low temperature region.The pressure dependence of thermal conductivity is also investigated for diferent length,width and thickness of few-layer graphene.Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons.Furthermore,it maybe indicate a so-called pressure-thermal efect in nanomaterials.

关键词：横向压力导热系数纳米带石墨分子动力学模拟控制压力依赖性纳米材料

Synthesis of Ta C and Ta_2C from tantalum and graphite in the laser-heated diamond anvil cell

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Chinese Science Bulletin 2014年第36期59卷 5283-5289页

作者： Lkhamsuren Bayarjargal Bjrn Winkler Alexandra Friedrich Erick A.Juarez-Arellano Institut fr Geowissenschaften Universitt FrankfurtAltenh ferallee 1 60438 Frankfurt am Main Germany Universidad del Papaloapan Circuito Central 200 Parque Industrial 68301 Tuxtepec Mexico

The pressure dependence of the onset of the formation of Ta C and Ta2 C from the elements has been investigated by in situ X-ray diffraction and pyrometry.Ta C has been synthesized by the reaction of Ta and graphite at pressures between 8.6 and 14.3 GPa and at temperatures up to 2,300 K using a laser-heated diamond anvil cell. The products were characterized by X-ray diffraction. Ta and graphite begin to react around 1,100 K at ambient pressure conditions, and the reaction temperature increases with increasing pressure. A linear extrapolation of these data is consistent with recent observations of the formation of Ta C at 90 GPa and 3,600 K. We show that diffusion of carbon into tantalum significantly changes the lattice parameter of up to 2 % in the pressure range of up to19 GPa. In some experiments, Ta2 C was formed concomitantly. The experimentally determined bulk modulus of Ta2 C is B0;exp:= 286(5) GPa. Other tantalum carbide phases were not observed.

关键词：细胞合成激光加热碳化钽金刚石石墨原位X射线衍射压力依赖性反应温度