“变形”的美学——从《变形记》看卡夫卡小说的话语方式

卡夫卡在创作 (如《变形记》)中运用的是一种变形的话语方式。它常以不可思议的开头 ,把主人公和读者一起“抛入”一个变了形的审美语境 :其叙事时间寓变化于简单、叙事体态采用复合式的双重视角、叙事语式多用虚拟语气和推测性词汇。这根源于卡夫卡“变形”的美学 ,包括他对人生的生存境况的“恐惧”体验和“滑动反论”

荒诞中的真实 现代人的困境——从卡夫卡的《变形记》到达里厄塞克的《母猪女郎》

本文认为 ,卡夫卡的《变形记》与玛丽·达里厄塞克的《母猪女郎》都以人形异变的荒诞故事在更高层次上表现了人类的生存困境 ,揭示了现代社会对人性的挤压 ,扭曲和戕害。不同的是 ,卡夫卡主要是出于人道主义的关怀 ,以格里高尔的异化及毁灭对冷酷荒诞的世界予以谴责和控诉 ,而达里厄塞克则是基于对人性的探寻和追求 ,不仅通过母猪女郎的不幸遭遇对非人性的现代社会进行鞭鞑 ,更以她的反叛和抗争来表现主体意识的高扬以及与荒诞世界的决裂。《变形记》采用的是一种“卡夫卡式”的冷峻笔调 ,而《母猪女郎》的叙事风格则大胆而活泼 ,是粗犷与庄严 。

生命的叩问:我是谁——宗璞的《我是谁》与卡夫卡的《变形记》之比较

基于时代背景的某些契合点,《我是谁》和《变形记》在主人公的无归属感,异化、孤独的主题,荒诞、变形的手法的运用上有相似之处。但由于文化背景、作家的人生观、世界观和家庭背景的差异,两篇小说在主题的属性,孤独、异化的程度,主人公悲剧结局的内涵上又有差异,这体现了作家宗璞立足本土,追求创新的意识。

绝望者的寓言——从《变形记》和《现实一种》看卡夫卡对余华的影响

本文从影响研究的角度,以《变形记》和《现实一种》为例,分析奥地利作家卡夫卡对中国先锋派作家余华的影响。 余华不仅在叙述风格上,而且在小说意义的处理方式上和情绪浸染方面,均与现代文学鼻祖卡夫卡遥相呼应。

剖析《变形记》的寓意及特色

本文对奥地利作家Franz Kafka(卡夫卡)的代表作《变形记》进行了分析,指出其作品中蕴含着深刻的内涵,以及平板而冷静的语言风格。

Crystallization of amorphous NiTi shape memory alloy fabricated by severe plastic deformation

Based on the local canning compression,severe plastic deformation（SPD） is able to lead to the almost complete amorphous nickel-titanium shape memory alloy（NiTi SMA）,in which a small amount of retained nanocrystalline phase is embedded in the amorphous matrix.Crystallization of amorphous NiTi alloy annealed at 573,723 and 873 K was investigated,respectively.The crystallization kinetics of the amorphous NiTi alloy can be mathematically described by the Johnson-MehlAvrami-Kolmogorov（JMAK） equation.NiTi SMA with a complete nanocrystalline phase is obtained in the case of annealing at 573 K and 723 K,where martensite phase transformation is suppressed due to the constraint of the grain boundaries.Crystallization of amorphous NiTi alloy at 873 K leads to the coarse-grained NiTi sample,where（001） martensite compound twin is observed at room temperature.It can be found that the martensitic twins preferentially nucleate at the grain boundary and they grow up towards the two different grains.SPD based on the local canning compression and subsequent annealing provides a new approach to obtain the nanocrystalline NiTi SMA.

Ni_(56)Mn_(25-x)Cr_xGa_(19)(x=0,2,4,6) high temperature shape memory alloys

The microstructure,martensitic transformation behavior,mechanical and shape memory properties of Ni56Mn25-xCrxGa19（x=0,2,4,6） alloys were investigated.Single phase of martensite with tetragonal structure is present for x=0,and dual-phase containing martensite and γ phase is observed for x≥2.The martensitic transformation peak temperatures decrease monotonically from 401 ℃ for x=0 to 197 ℃ for x=6.The introduction of γ phase by Cr addition is proved to be effective in improving the workability and ductility.The tensile stress and strain are 497 MPa and 8 % for x=4,and 454 MPa and 5.5 % for x=6,respectively.The shape memory strain values are 2.7 % under a residual strain of 4.5 % for x=4,and 1.9 % under a residual strain of 3.5 % for x=6,respectively.

Influence of cooling rate on phase transformation and microstructure of Ti-50.9%Ni shape memory alloy

Heat treatment of Ti-50.9%Ni （mole fraction） alloy was studied by differential scanning calorimetry, X-ray diffraction, scanning electron microscopey and energy dispersive X-ray analysis to investigate the influence of cooling rate on transformation behavior and microstructures of NiTi shape memory alloy. The experimental results show that three-stage phase transformation can be induced at a very low cooling rate such as cooling in furnace. The cooling rate also has a great influence on the phase transformation temperatures. Both martensitic start transformation temperature （Ms） and martensitic finish transformation temperature （Mf） decrease with the decrease of the cooling rate, and decreasing the cooling rate contributes to enhancing the M→A austenite transformation temperature. The phase transformation hysteresis （Af-Mf） increases with the decrease of the cooling rate. Heat treatment is unable to eliminate the textures formed in hot working of NiTi sample, but can weaken the intensity of them. The cooling rate has little influence on the grain size.

Constitutive equation and processing map of equiatomic NiTi shape memory alloy under hot plastic deformation

In order to describe the deformation behavior and the hot workability of equiatomic NiTi shape memory alloy (SMA) during hot deformation, Arrhenius-type constitutive equation and hot processing map of the alloy were developed by hot compression tests at temperatures ranging from 500 to 1100 °C and strain rates ranging from 0.0005 to 0.5 s?1. The results show that the instability region of the hot processing map increases with the increase of deformation extent. The instability occurs in the low and high temperature regions. The instability region presents the adiabatic shear bands at low temperatures, but it exhibits the abnormal growth of the grains at high temperatures. Consequently, it is necessary to avoid processing the equiatomic NiTi SMA in these regions. It is preferable to process the NiTi SMA at the temperatures ranging from 750 to 900 °C.

Thermo-mechanical Behaviors of Functionally Graded Shape Memory Alloy Timoshenko Composite Beams

This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam theory.The volume fraction of SMA fiber is graded in the thickness of beam according to a power-law function and the equivalent parameters are formulated.The governing differential equations,which can be solved by direct integration,are established by employing the composite laminated plate theory.The influences of FG parameter,ambient temperature and SMA fiber laying angle on the thermo-mechanical behaviors are numerically simulated and discussed under different boundary conditions.Results indicate that the neutral plane does not coincide with the middle plane of the composite beam and the distribution of martensite is asymmetric along the thickness.Both the increments of the functionally graded parameter and ambient temperature make the composite beam become stiffer.However,the influence of the SMA fiber laying angle can be negligent.This work can provide the theoretical basis for the design and application of FG SMA structures.

Microstructure, martensitic transformation and mechanical properties of Ni-Mn-Sn alloys by substituting Fe for Ni

The effects of partial substitution of Fe element for Ni element on the structure,martensitic transformation and mechanicalproperties of Ni50-xFexMn38Sn12(x=0and3%,molar fraction)ferromagnetic shape memory alloys were investigated.Experimentalresults indicate that by substitution of Fe for Ni,the microstructure and crystal structure of the alloys change at room temperature.Compared with Ni50Mn38Sn12alloy,the martensitic transformation starting temperature of Ni47Fe3Mn38Sn12alloy is decreased by32.5K.It is also found that martensitic transformation occurs over a broad temperature window from288.9to352.2K.It is found that themechanical properties of Ni-Mn-Sn alloy can be significantly improved by Fe addition.The Ni47Fe3Mn38Sn12alloy achieves amaximum compressive strength of855MPa with a fracture strain of11%.Moreover,the mechanism of the mechanical propertyimprovement is clarified.Fe doping changes the fracture type from intergranular fracture of Ni50Mn38Sn12alloy to transgranularcleavage fracture of Ni47Fe3Mn38Sn12alloys.

Microstructure evolution and deformation behavior of as-cast NiTi shape memory alloy under compression

The as-cast ingot of equiatomic nickel-titanium shape memory alloy （SMA） was prepared via vacuum consumable arc melting. Differential scanning calorimetry （DSC）, X-ray diffraction （XRD） analysis, energy dispersive X-ray （EDX） measurement and microanalysis were adopted in order to understand the microstructure evolution and deformation behavior of the as-cast NiTi SMA under compression at various strain rates and temperatures. The microstructures of as-cast NiTi SMA composed of dendritic grains and equiaxed grains are inhomogeneous and show segregation. The as-cast NiTi SMA consists of B19′ martensite, B2 austenite and Ti2Ni phase simultaneously at room temperature. The as-cast NiTi SMA is sensitive to strain rate under compression at high temperature, at which NiTi SMA is characterized by dynamic recrystallization at strain rates of 0.1 and 0.01 s-1, but by dynamic recovery at strain rate of 0.001s-1. The strain rates have little influence on the true stress—strain curves as well as microstructure of NiTi SMA at room temperature and -100 °C.

Superelastic properties of nanocrystalline NiTi shape memory alloy produced by thermomechanical processing

Effects of thermomechanical treatment of cold rolling followed by annealing on microstructure and superelastic behavior of the Ni50Ti50 shape memory alloy were studied.Several specimens were produced by copper boat vacuum induction melting.The homogenized specimens were hot rolled and annealed at 900°C.Thereafter,annealed specimens were subjected to cold rolling with different thickness reductions up to 70%.Transmission electron microscopy revealed that the severe cold rolling led to the formation of a mixed microstructure consisting of nanocrystalline and amorphous phases in Ni50Ti50 alloy.After annealing at 400°C for 1 h,the amorphous phase formed in the cold-rolled specimens was crystallized and a nanocrystalline structure formed.Results showed that with increasing thickness reduction during cold rolling,the recoverable strain of Ni50Ti50 alloy was increased during superelastic experiments such that the 70%cold rolled-annealed specimen exhibited about 12%of recoverable strain.Moreover,with increasing thickness reduction,the critical stress for stress-induced martensitic transformation was increased.It is noteworthy that in the 70%cold rolled-annealed specimen,the damping capacity was measured to be 28 J/cm3 that is significantly higher than that of commercial NiTi alloys.

Thermo-electric behaviour of NiTi shape memory alloy

The thermo-electric behavior of shape memory alloy （SMA） wire was presented. When the wire was electrically heated above its transformation temperature by current, a large mechanical force is exerted due to transformation in its phases. In order to make use of SMA wire as an actuator, different parameters and their relationships were investigated. These parameters are recoverable strain （displacement）, temperature hysteresis and electrical resistance variation under different stress levels. Optimum safe heating current was assessed and phase transformation temperatures were estimated by heat transfer model. The wire was heated and cooled by 680 mA of current for 796 s under natural air convection. The strain recovered is 4.33% and corresponding change in resistance is 11.2% at 43 MPa of stress. The resistance variation shows linearly with displacement and current during heating and cooling cycle respectively. This study will be useful in precisely controlling of SMA wire actuator with and without external sensor feedback.

A Note on the Solution of Water Wave Scattering Problem Involving Small Deformation on a Porous Channel-Bed

The solution of water wave scattering problem involving small deformation on a porous bed in a channel, where the upper surface is bounded above by an infinitely extent rigid horizontal surface, is studied here within the framework of linearized water wave theory. In such a situation, there exists only one mode of waves propagating on the porous surface. A simplified perturbation analysis, involving a small parameter ε （≤1） , which measures the smallness of the deformation, is employed to reduce the governing Boundary Value Problem （BVP） to a simpler BVP for the first-order correction of the potential function. The first-order potential function and, hence, the first-order reflection and transmission coefficients are obtained by the method based on Fourier transform technique as well as Green＇s integral theorem with the introduction of appropriate Green＇s function. Two special examples of bottom deformation： the exponentially damped deformation and the sinusoidal ripple bed, are considered to validate the results. For the particular example of a patch of sinusoidal ripples, the resonant interaction between the bed and the upper surface of the fluid is attained in the neighborhood of a singularity, when the ripples wavenumbers of the bottom deformation become approximately twice the components of the incident field wavenumber along the positive x -direction. Also, the main advantage of the present study is that the results for the values of reflection and transmission coefficients are found to satisfy the energy-balance relation almost accurately.

A molecular dynamics investigation of the deformation mechanism and shape memory effect of epoxy shape memory polymers

Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics(MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.

Softening micromechanical constitutive model of stress induced martensite transformation for NiTi single crystal shape memory alloy

Based on the assumption of laminated microstructure, a micromechanical model of stress induced martensite transformation for NiTi shape memory alloys single crystal is proposed. Elasticity anisotropy and different proper-ties for two phases are considered. Martensite volume fraction is chosen as the internal variable that controls the phase transformation quantitatively. An effective macroscopic elasticity matrix based on the different elasticity characteristics of each phase and the martensite volume fraction are obtained with the help of the perfect interfa-cial relationships. A phase transformation driving force is derived to construct the transformation criterion. The model corresponds to a non-convexity free energy function during phase transformation, so softening behavior can be well simulated by the model. A numerical simulation is implemented for the uniaxial loading of NiTi single crystal alloy according to the model, and simulation results are proved by experimental results of polycrystal with strong {111} texture. Superelasticity, Anisotropy, the evolution of microstructure and softening behavior can be well simulated.

Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons

The influence of stresses on martensitic transformation in Ni50Mn19Fe6Ga25 melt-spun ribbons was studied. X-ray diffraction examination shows that the ribbon has a pure cubic L21 phase at room temperature and that the ribbon surface exhibits [100] preferentially oriented texture, while the [110] axis is about 45° tilted from the normal of the ribbon. By calculating the d spacing at different angles with the length direction of the ribbon, the tension was observed. It was found that the direction of the stress was along [010] direction of the oriented textured grains. During cooling, there is no obvious structural transition observed in as-spun ribbons. However, when the ribbons were annealed at 900 K for 24 h, the tension along [010] direction disappeared and the structural transition from cubic to tetragonal occurred obviously during cooling. It indicates that it is the tension along [010] direction to suppress the martensitic transformation in the as-spun ribbons.

Composition dependent elastic modulus and phase stability of Ni_2MnGa based ferromagnetic shape memory alloys

Ni2MnGa based ferromagnetic alloys are ideal candidates for applications such as actuators, magnetic refrigerators or magne-tostrictive transducers due to their attractive properties such as magnetic field induced shape memory effect and large magnetocaloric effect. The properties of these alloys （e.g., the martensitic transformation temperature TM） sensitively depend on the composition. Understanding the composition dependence of these properties so as to design the alloy as desired is one of the main research topics in this area. In recent years, we have investigated the composition dependent elastic modulus and phase stability of Ni2MnGa-based alloys by using a first-principles method, in hope of clarifying their connection to the properties of these alloys. In this article, we review the main results of our investigations. We show that the tetragonal shear modulus C＇ is a better predictor of the composition dependent TM than the number of valence electrons per atom （e/a） since the general TM-C＇ correlation works for some of the alloys for which the TM-ela correlation fails, although there exist several cases for which both the general TM-C＇ and TM-ela correlations break down. Employing the experimentally determined modulation function, the complex 5-layer modulated （5M） structure of the martensite of Ni2MnGa and the Al-doping effect on it are studied. We find that the shuffle and shear of the 5M structure are linearly coupled. The relative stability of the austenite and the marten- sites is examined by comparing their total energies. The non-modulated martensite β＇″ with the tetragonality of the unit cell c/a〉1 is shown to be globally stable whereas the 5M martensite with c/a〈1 is metastable. The critical Al atomic fraction over which the martensitic transformation between the 5M martensite and austenite cannot occur is predicted to be 0.26, in reason- able agreement with experimental findings.