苯肼对红细胞在体衰老过程中微观流变特性的影响

:在Brunara等人用苯肼使动物造成急性溶血性贫血的方法基础上 ,建立一种由急性溶血性贫血后 ,而诱发家兔幼红细胞增多的非正常生理状态的红细胞在体衰老模型 ,继而研究新生红细胞从产生到死亡过程 ,即衰老过程的流变学特性的变化规律。通过对新生红细胞的压积、变形、取向及与之相应的全血的粘度、血沉等指标的连续60多天的监测 ,发现红细胞在衰老过程中的微观流变学特性确实有明显改变。红细胞在体衰老过程中微观流变特性逐渐变差。

^(60)Co辐射对在体红细胞微观流变特性的影响

采用 60Co大剂量全身均匀急性辐射的方法,使动物造血系统受到严重破坏,造血机能大大减弱,在大约30天时间内,循环系统中的红细胞计数明显下降,从而造成一种辐射贫血的动物模型。以便较长时间内连续研究60Co大剂量辐射对在体红细胞流变特性的影响。采用一种在低粘切变流场中能将红细胞变形指数DI分解为取向指数 (DI)or和小变形指数 (DI)d的新型激光衍射法 [1],研究了 60Co大剂量辐射对在体红细胞变形性、全血粘度、沉降率和红细胞计数等血液流变学特性的影响 ,并与正常对照组红细胞的相应参数作比较 ,发现在60Co大剂量辐射后 ,开始这些参数变得明显异常 ,40天后逐渐接近于正常对照组水平。这表明 60Co大剂量急性辐射对动物体内造血系统的影响是长期的、严重的。将这种 60Co辐射造成的贫血模型与文宗曜等提出的用抗体诱导的大量同步化的球形红细胞贫血模型相比较 ,发现后者作为在体贫血动物模型具有更明显的优点。同时为研究辐射对血液流变特性的影响及正确地挑选红细胞衰老模型提供了理论与实验的基础。

神经氨酸酶对红细胞微观流变特性的影响

用生物化学方法 ,即用不同剂量的神经氨酸酶 (唾液酸酶 )作用相同的时间 ,和用相同剂量的神经氨酸酶作用不同的时间分别对红细胞进行处理 ,以达到不同程度地去掉其表面电荷。测量处理过的血液的粘度、血沉、红细胞聚集及各样本红细胞的DI、(DI) or、(DI) d 在不同切变率下的变形曲线 ,即DI γ、(DI)or γ和 (DI)d γ曲线及电泳率 ,并与正常对照组红细胞的相应参数及曲线作比较 ,发现两者之间的粘度、血沉、红细胞聚集及各种曲线存在明显差异。由此表明 ,红细胞表面电荷的多少直接影响血粘度、血沉及红细胞聚集与其红细胞变形性等流变特性 ,有力地证明了在低切变率下血液粘度与血沉主要反映红细胞的聚集行为 ,而在高切变率下的血液粘度则主要反映红细胞的变形行为。

苯肼对兔网织红细胞微观流变学特性影响的研究

目的利用苯肼注入造成的动物贫血模型,对兔网织红细胞微观流变学特性进行研究。总结兔网织红细胞微观流变学特性的变化规律。方法采用苯肼注入动物体内,能使动物造成贫血,从而诱发动物幼红细胞增多症,造成一种贫血的动物模型。在几天内连续研究苯肼对新生的网织红细胞及红细胞流变学特性的影响。采用一种在低粘切变流场中能将红细胞变形指数(DI)分解为取向指数(DI)or和小变形指数(DI)d的新型激光衍射法[1],对网织红细胞及红细胞的变形指数、取向指数、综合变形指数(IDI)等血液流变学特性参数进行测量。结果注入苯肼后,新生的网织红细胞流变学特性与成熟红细胞流变学特性存在明显异常,网织红细胞的变形指数、取向指数、和小变形指数与成熟红细胞的相应指数存在明显异常。结论网织红细胞流变学特性与成熟红细胞流变学特性存在明显异常,为研究苯肼对网织红细胞及红细胞的血液流变学特性的影响提供了理论与实验基础。

^(60)Co辐射对网织红细胞微观流变学特性的影响

采用 60 Co大剂量全身均匀急性辐射的方法 ,造成一种辐射贫血的动物模型 .以便在几天内连续研究 60 Co辐射对新生的网织红细胞及红细胞流变学特性的影响 .采用一种在低粘切变流场中能将红细胞变形指数DI分解为取向指数 (DI) or和小变形指数 (DI) d 的新型激光衍射法 ,对网织红细胞及红细胞的变形指数、取向指数、综合变形指数 (IDI)等血液流变学特性参数进行测量 ,发现在 60 Co大剂量辐射后 ,新生的网织红细胞及红细胞流变学特性存在明显异常 .将这种 60 Co辐射造成的贫血模型与文宗曜等提出的用抗体诱导的大量同步化的球形红细胞贫血模型相比较 ,后者更具有明显的优点 .同时为研究辐射对血液流变特性的影响及正确地挑选红细胞衰老模型提供了理论与实验的基础 .

在体网织红细胞微观流变学特性

用苯肼使动物造成急性溶血性贫血的方法, 诱发动物体内新生网织红细胞大量增多, 通过对新生网织红细胞的变形、取向及电泳率等指标的连续72 h的测量, 发现网织红细胞在转变为成熟红细胞的过程中, 其流变学特性有明显改变. 这对研究由于贫血等原因造成的网织红细胞增多情况下全血的微观流变学特性有重要的临床意义, 同时也对新生网织红细胞的微观流变学特性进行了系统研究.

废橡胶粉改性沥青的微观结构与流变特性

采用扫描电镜(SEM)及动态力学(DSR)的方法研究了废橡胶粉改性沥青的微观结构和流变性能。结果表明,废橡胶粉在基质沥青中分散均匀,能很好地吸附沥青,形成稳定的非均相结构;废胶粉改性沥青的复数模量随频率的增加而增大,随温度的升高而减小,沥青逐步转变为粘流态。采用时间温度换算法则得到的频率主曲线可以涵盖路面整个交通状况;对移位因子拟合,高温时WLF方程拟合效果较好,低温时宜采用二次多项式拟合。了解废橡胶粉改性沥青的微观结构及流变性能,为合理应用废橡胶粉改性沥青提供理论支持和技术保障。

Increasing the toughness while reducing the viscosity of carbon nanotube/ polyether imide/polyether ether ketone nanocomposites

Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether imide(PEI)were pre-pared by a direct wet powder blending method using a vertical injection molding machine.The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50%while producing an increase in the toughness of the nanocom-posites,whose strain to failure increased by 129%,and fracture energy increased by 97%.The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance.This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.

Flow softening behavior and microstructure evolution of Al-5Zn-2Mg aluminum alloy during dynamic recovery

The flow stress behavior and microstructure development of Al-5Zn-2Mg （7005） aluminum alloy were studied by hot compression tests at deformation temperatures between 300-500 ＆#176;C and strain rates between 0.05-50 s-1. The deformed structures of the samples were observed by optical microscopy （OM）, transmission electron microscopy （TEM） and electron backscattering diffraction （EBSD） analysis. The calculated activation energy is 147 kJ/mol, which is very close to the activation energy for lattice self-diffusion in aluminum （142 kJ/mol）. Dynamic recovery is the dominant restoration mechanism during the deformation. At high strain rate of 50 s-1, temperature rise due to deformation heating leads to a significant flow softening. Microstructure observations indicated that the remaining softening after deformation heating correction at high strain rate and the softening observed at high temperature are associated with grain coarsening induced by grain boundary migration during dynamic recovery process.

油基钻井液用乳化剂油/水界面吸附及对乳液结构的影响

在油基钻井液中,乳化剂在油/水界面的吸附行为对乳化稳定性及乳化机理影响极大。利用界面扩张流变技术研究了油基钻井液用主乳化剂PF-BIOEMUL与油基钻井液用辅乳化剂PF-BIOCOAT对油/水动态界面张力及界面黏弹性的影响,并考察了PF-BIOEMUL与PF-BIOCOAT配制乳液的微观流变性。研究表明,PF-BIOEMUL的主要功能是提供弹性模量,提高油/水界面膜强度高,最佳加量为2.0%。PF-BIOCOAT的主要功能是提供黏性模量,降低油/水界面张力,最佳用量为1.5%。PF-BIOEMUL和PF-BIOCOAT可以同时吸附到油/水界面上,保证了乳化体系既具有较低的油/水界面张力,又有较好的界面膜稳定性,所形成的乳液具有三维网状结构,稳定性良好。这些研究为油基钻井液体系稳定性研究提供了理论基础。图11参21。

Microstructure control of AZ31 alloy by self-inoculation method for semisolid rheocasting

A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy （self-inoculants）, subsequently pouring the mixed melt into a special designed multi-stream fluid director. The primary phase with dendritic morphology in the conventionally cast AZ31 alloy has readily transformed into near spherical one in the slurry produced by SIM from melt treatment temperature between 690 ℃ and 710 ℃ and self-inoculants addition of 3%-7%. Achievement of the non-dendritic microstructure at the higher melt treatment temperature requires more self-inoculants addition or decreases in the slope angle of fluid director. Primary phase in the slurry thus produced has attained an ideally globular morphology after isothermal holding at 620 ℃ for 30 s. The increasing holding time leads to decrease of shape factor but the coarsening of particle size. The spheroidization and coarsening evolution process of solid particles during the isothermal holding were analyzed by Lifshitz-Slyozov-Wagner （LSW） theory.

Hot deformation behavior and microstructural evolution of Al-Zn-Mg-0.25Sc-Zr alloy during compression at elevated temperatures

The hot deformation behavior of Al-Zn-Mg-0.25Sc-Zr alloy and its microstructural evolution were investigated by isothermal axisymmetric hot compression tests at temperatures from 340 to 500°C and strain rates ranging from 0.001 to 10 s -1 .The steady flow stress increased with increasing the strain rate or decreasing the deformation temperature,which can be described by a hyperbolic-sine constitutive equation with the deformation activation energy of 150.25 kJ/mol.The tendency of dynamic recrystallization enhanced at high deforming temperatures and low strain rates,which corresponded to low Z values.With decreasing Z value,the main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization, correspondingly,the subgrain size increased and the dislocation density decreased.

Effects of technical parameters of continuous semisolid rolling on microstructure and mechanical properties of Mg-3Sn-1Mn alloy

A sloping semisolid rheo-rolling process of Mg-3Sn-1Mn alloy was developed, and the effects of process parameters on the microstructure and mechanical properties of Mg-3Sn-lMn alloy strip were studied. The results show that the primary grain average diameter of the strip increases with the increase of the roll speed. The primary grain average diameter decreases firstly and then increases with the increase of the vibration frequency, and the tensile strength and elongation of the strip increase firstly and then decrease with the increase of the vibration frequency. The primary grain average diameter increases with the increase of casting temperature, and the tensile strength and elongation of the strip decrease correspondingly. When the casting temperature is 670℃, the roll speed is 52 mm/s, and the vibration frequency is 60 Hz, Mg-3Sn-1Mn alloy strip with good properties is produced. The mechanical properties of the present product are higher than those of Mg-3Sn-lMn alloy casting with the addition of 0.87% Ce （mass fraction）.

Viscosity profile prediction of a heavy crude oil during lifting in two deep artesian wells

It has been known that the productivity of artesian wells is strongly dependent on the rheological properties of crude oils. This work targets two deep artesian wells(>5000 m) that are producing heavy crude oil. The impacts of well conditions including temperature, pressure and shear rate, on the crude oil rheology were comprehensively investigated and correlated using several empirical rheological models. The experimental data indicate that this heavy oil is very sensitive to temperature as result of microstructure change caused by hydrogen bonding. The rheological behavior of the heavy oil is also significantly impacted by the imposed pressure, i.e., the viscosity flow activation energy(Eμ) gently increases with the increasing pressure. The viscosity–shear rate data are well fitted to the power law model at low temperature. However, due to the transition of fluid feature at high temperature(Newtonian fluid), the measured viscosity was found to slightly deviate from the fitting data. Combining the evaluated correlations, the viscosity profile of the heavy crude oil in these two deep artesian wells as a function of well depth was predicted using the oilfield producing data.

Effect of jet milling on micro-strain behavior and rupture behavior of agglomerates of ultrafine WC powders

The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.

Effects of rheoforming on microstructures and mechanical properties of 7075 wrought aluminum alloy

It is economically advantageous to cast wrought aluminum alloys directly into near-net-shape components.The objective of the present work is to take advantage of the rheoforming with 7075 alloy to improve the competitiveness of this emerging technology in the manufacture of wrought aluminum alloy.High quality semi-solid slurry was produced,in which primary α(Al) presents in diameter of 62 μm and shape factor of 0.78 and features no eutectics entrapped.Higher forming pressure results in small grain size,improved shape factor and higher density.Especially,rheoforming can effectively reduce the occurrence of hot tearing.The average yield strength and elongation of the rheoformed samples in the T6 condition are 483 MPa and 8%,respectively.

Rheological catastrophic model for soft clays

A brief review of the former studies on the mechanisms of soil rheology and microstructure is presented. Then a microstructure model and a set of rheological constitutive relations for sott clays, which describe how the rheological consolidation settlement develops, are established in the framework of the catastrophe theory. The validity of this model is verified by a series of rheological consolidation experiments with different loading rates. The experimental data show that creep deformation can be clearly observed in these tests, and the consolidation settlement is loading rate dependent. The characteristics of the deformation can be explained and reproduced successfully using the model. It can be concluded that only the biggest set of voids would collapse for one load increment. Parameters in the model, k and η, are gained by curve fitting. With only two free parameters, good fits of the data are achieved.

Microstructure, morphology, crystallization and rheological behavior of impact polypropylene copolymer

Impact polypropylene copolymer (IPC), named polypropylene catalloy, not only possesses excellent impact property, but also presents good rigidity. Its superior performances result from the complicated composition and microstructure. In the present article, recent progress in the studies on microstructure, morphology, crystallization and rheological behavior of IPC is summarized, and findings of the authors and their collaborators are reported. In general, IPC is divided into three components, i.e., ethylene-propylene random copolymer (EPR), a series of different segment lengths ethylene-propylene copolymer (EbP) and propylene homopolymer. The reasonable macromolecular structures of EbP and a multilayered core-shell model of dispersed phase structure in IPC were proposed, in which the dispersed phase consists of an outer EbP shell, an inner EPR layer and an EbP core. It is found that the annealing at melt-state may lead to an abnormal phase inversion, and the phase inversion disappears when temperature cools down to room temperature. The cause of phase inversion is ascribed to the existence of EbP component, which results in the stronger activity of the dispersed phase. The crystalline structure and morphologic results confirm the formation of β-iPP in IPC. Furthermore, it is found that the ethylene content in IPC and cooling rate of the samples have an important influence on the formation of β-iPP. Based on the crystallization kinetics analyzed by Lauritzen-Hoffman theory, crystallization behavior of different IPC samples is discussed and it is proposed that the dilution effect of ethylene propylene copolymer has a more remarkable influence on surface nucleation than on crystal growth. In addition, annealing at high temperature can result in the changes of chain structure for IPC, and this instability is ascribed to the oxidative degradation and crosslink reaction mainly in iPP component.

Impact of structure and flow-path on in situ synthesis of AlN: Dynamic microstructural evolution of Al-AlN-Si materials

The AI-AIN-Si composites were prepared in the gas-in-liquid in situ synthesized flow-reaction-system, which was implemented by a powder metallurgy and reaction sin- tering route. The experimental results showed that A1-AIN- 50SiB material （prepared by ball-milling powders） and AI- AIN-50SiM material （prepared by mixing powders） exhibited the semi-continuous Si structures and the isolated Si islands, respectively. Subsequently, the AI-AIN-50Si materials were selected as the model materials by phase identification and microstructure analysis. The dynamic microstructural evolu- tion of AI-AIN-50Si materials was investigated using the computational fluid dynamics （CFD） method. Mathematical models and simulation results showed that the in situ synthesis of AIN was strongly influenced by the structure and the flow- path （（Cg,N2/lg,N2）＋（Cs,AlN/ls,AiN））. The flow paths of AI-AIN-50Si^B material were restricted by the semi-continuous Si. These Si structures can promote the formation of the strong turbulence with gradually weakened fluctuation, so that the in situ synthesis of AIN was interconnected and surrounded by an interpenetrating Si network. In contrast, the flow paths of AI- AIN-50Si^B material can easily pass through the isolated Si due to its mild turbulence with linear relationship. As a result, AIN was separated by the isolated Si and agglomerated in the matrix. Overall, the present work provides new insights into dynamic microstructural evolution in in situ reaction sinter- ing systems.

Rheology and microstructure effects of waste spent coffee grounds in modifying asphalt binder

Herein the biowaste by-product spent coffee grounds(SCGs)from coffee industry were incorporated into asphalt binders for performance enhancement.From the analysis of Fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC),dynamic shear rheometer(DSR),and Brookfield viscosity rheometer,it is confirmed that SCGs have potential prospects as bio-waste modifiers in the application of sustainable pavements.Results demonstrated that the modification process was mainly based on physical reinforcement.Compared with that of the neat asphalt,the shearing stress-resistant ability and high-temperature performance of the SCGs modified binders with the appropriate addition presented a bit of improvement;whereas the binders with 1%and 3%SCGs exhibited remarkably enhanced low-temperature stability.However,notable weaknesses of practical performance were shown for the binder with excessive content of SCGs,indicating the necessity of proportion selecting before application.