Incomplete Transition Research Articles

New cyanido-bridged iron(II) spin crossover coordination polymers with an unusual ladder-like topology: an alternative to Hofmann clathrates.

Two new cyanido-bridged {FeIIMII} double chains were obtained by reacting cyanido anions [M(CN)4]2- with complex cations [FeII(tptz)]2+ (preformed in situ by mixing a hydrated tetrafluoroborate salt of iron(II) and a tptz ligand, tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine) having the general formula [FeII(tptz)MII(CN)4]·2H2O·CH3CN, where M = Pd (1) or Pt (2). Additionally, two molecular complexes formulated as [FeII(tptz)2][MII(CN)4]·4.25H2O, where M = Pd (3) or Pt (4), were subsequently obtained from the same reaction, as secondary products. Single crystal X-ray analysis revealed that 1 and 2 are isostructural and crystallize in the P-1 triclinic space group. Their structure consists of a double-chain with a ladder-like topology, in which cyanido-based [M(CN)4]2- metalloligands coordinate, through three CN- ligands and three [FeII(tptz)]2+ complex cations. Compounds 3 and 4 are also isostructural and crystallize in the P1̄ triclinic space group, and the X-ray structural data show the formation of [FeII(tptz)2]2+ and [MII(CN)4]2- ionic units interconnected through H-bonds and π⋯π stacking supramolecular interactions. The static DC magnetic measurements recorded in the temperature range of 2-300 K showed that 1 and 2 exhibit incomplete spin transition on cooling, which is also confirmed by single crystal XRD analysis and Mössbauer spectroscopy. Compounds 3 and 4 are diamagnetic, most likely due to the encapsulation of Fe(II) in a tight pocket formed by two tptz ligands that preserve the low-spin state in the temperature range of 2-400 K.

Protocol-based Control for Hidden Markov Jump Systems With Incomplete Transition Descriptions Against Injection Attacks

Protocol-based Control for Hidden Markov Jump Systems With Incomplete Transition Descriptions Against Injection Attacks

Reliable quantized sampled‐data LFC for semi‐Markov jump interconnected multi‐area power systems: Dealing with incomplete TRs

AbstractThis article aims to address the reliable quantized sampled‐data load frequency control (LFC) synthesis problem for semi‐Markov jump interconnected multi‐area power systems (IMAPSs) suffering from incomplete transition rates (TRs) and actuator failures. Primarily, the semi‐Markov process configurated with incomplete TRs is utilized to model the structural and coefficient switchings of IMAPSs, which enables a more precise representation of reality and a wider range of application. Subsequently, in order to reduce the control cost and facilitate data processing, an aperiodic quantization sampling mechanism is introduced. Furthermore, a mode‐dependent and comprehensive actuator faulty model is scheduled to portray various stochastically occurring actuator failures, which is more in line with practical application. Then, by fully utilizing the state information of sampled intervals, a two‐sided looped functional with some matrices that are not required to be strictly positive is constructed to enhance the flexibility. In what follows, on the basis of stochastic analysis technique and looped functional, sufficient conditions with two scenarios are established in the form of linear matrix inequalities (LMIs) to guarantee the stochastic stability with an performance of the resultant semi‐Markov jump IMAPSs. Finally, the effectiveness of the proposed control synthesis methodology is validated through a numerical simulation.

A comparative study of microstructure and corrosion resistance in DP980 steel joints under different laser welding method

Three different laser welding methods were used to welding 2 mm DP980 steel butt joint, which were laser welding, laser-TIG hybrid welding and laser powder feeding (CoCrNi) welding respectively. An observational analysis was carried out in terms of microstructure, mechanical properties and corrosion resistance. It was discovered that a central microstructure of laser welding and laser-TIG hybrid welding the weld was dominated by slatted martensite. The laser powder feeding welding has resulted in a remarkable reduction of cylindrical crystals and an increased number of isometric crystals in weld center due to the addition of CoCrNi powder. Microstructure was further refined in incomplete phase transition zone by three different laser welding methods. The tempered martensite was also formed in the tempering zone, which softened the joint. The hardness values decreased considerably and tensile samples were also fractured at this location. Comparison with corrosion resistance of their joints through polarization curves and impedance spectra shows that laser powder feeding joint > laser joint > laser-TIG hybrid joint. The corrosion resistance of laser and laser-TIG hybrid joints in the base metal (BM) > heat affected zone (HAZ) > weld zone (WZ) is shown based on scanning vibrating electrode technique (SVET) localized area testing data at different time intervals. The laser powder feeding welding enhances the density of passivation film by reacting Cr to form Cr2O3, thereby improving corrosion resistance of entire joint.

Substituent group tuned structural dimensionalities and magnetic properties of V-shaped bis-pyridyl ligands based Fe(II) coordination polymers

A series of V-shaped thioether-based bis-pyridyl ligands containing different substituent groups have been successfully employed to assemble Fe(II)-based complexes by using H-tube diffusion method, resulting in six new coordination polymers with different structure types, [Fe(L1)(SCN)2]n·1.5nCH3OH (1), [Fe(L1)(SeCN)2]n·nCH3OH·nH2O (2), [Fe(L2)(SCN)2]n (3), [Fe(L2)(SeCN)2]n (4), [Fe(L3)(SCN)2]n (5), [Fe(L3)(SeCN)2]n (6) (L1 = 1,3-bis((pyridin-4-ylthio)methyl)benzene, L2 = 4,4′-(((2,4,6-trimethyl-1,3-phenylene)bis(methylene))bis(sulfanediyl))dipyridine, L3 = 4,4′-(((perchloro-1,3-phenylene)bis(methylene))bis(sulfanediyl))dipyridine). All the complexes have been structurally characterized by elemental analysis, FT-IR spectroscopy, single crystal and powder X-ray diffraction. The single crystal structure analysis revealed the one-dimensional (1D) chain for complexes 1–4, in which the different conformation the ligand adopted was found, and two-dimensional (2D) grid-like network for 5 and 6, respectively. Investigation of the temperature dependent magnetic susceptibilities discovered the always high spin state of the Fe(II) ion in all the compounds within the whole temperature range of 10-300 K, except complex 2 with the obvious temperature dependent color change from yellow (293 K) to violet (100 K). The thermo- and photomagnetic property study for complex 2 showed the incomplete spin transition behavior with interesting light-induced excited spin state trapping effect (LIESST). The current results indicated that the steric effect and/or the electronegativity of the substitute groups on the ligand and the conformation of the ligand could play an important role on the topologic structure of the target products, therefore putting obvious influence on spin state of the central Fe(II) ion.

Installing Democracy

Transitional justice is a framework for dealing with past atrocities that are on such a large scale and so horrific that the usual institutions and justice system are unable to adequately address them. Countries in Latin America that transitioned from dictatorship to democracy in the 1980s pursued transitional justice when deciding how to meet the demands of victims and what to do with perpetrators. The interdisciplinary field of transitional justice studies is robust within the social sciences and law. Yet artistic production engages in dialogues with the official and unofficial stories of the dictatorships and their legacies and also contributes to understanding transitions to democracy. This essay examines how visual art in Uruguay engages with transitional justice and memory of the dictatorship (1973–85), taking as a case study the installation Artista de mierda (Artist of Shit, 2019) by Fernando Barrios (b. 1968). Nearly four decades after Uruguay began its democratic transition, the struggle over which narratives would dominate the collective memory of state terror and what society should do about the open wounds of the dictatorship continues to be negotiated. Beyond merely reflecting common discourses about the dictatorship and democracy, Artista de mierda engages with the memory of state violence and reveals how Uruguay’s incomplete transition to democracy and its embrace of neoliberalism exacerbate inequality and create conditions for certain political figures and artists to rise to prominence within their respective fields.

Combined Experimental and Mechanoelastic Modeling Studies on the Low-Spin Stabilized Mixed Crystals of 3D Oxalate-Based Coordination Materials.

Structural studies involving single-crystal and powder X-ray diffraction analysis have been performed on dehydrated coordination networks of the [NixCo1-x(bpy)3][LiCr(ox)3] series, 0 ≤ x ≤ 1, (bpy = 2,2'-bipyridine). The high-symmetry cubic 3D structure of these materials is formed by oxalate anions bridging alternating Cr3+ and Li+ ions into an anionic framework, which contains large cavities that incorporate the [NixCo1-x(bpy)3]2+ cations. Irrespective of the Co/Ni ratio, all of the mixed samples are phase-pure and retain the high-symmetry cubic structure, with the lattice parameters gradually decreasing upon increasing Ni(II) concentration. The influence of the Ni(II) dilution on the magnetic behavior of these materials is substantial. For pure [Co(bpy)3][LiCr(ox)3], a gradual but incomplete thermal spin-crossover is evident due to the effect of the chemical pressure applied by the [LiCr(ox)3]2- framework, which stabilizes the low-spin (LS) 2E state relative to the high-spin (HS) 4T1 state of the Co(II) ion. Upon increasing the Ni(II) content, the spin-crossover becomes even more gradual and incomplete and eventually is not observed for pure [Ni(bpy)3][LiCr(ox)3]. The average spin-crossover temperature increases with the increasing Ni(II) content, suggesting a higher degree of chemical pressure applied by the oxalate framework manifested by changing the ΔE0HL toward positive values. The magnetic behavior of all these framework materials has been explained by the mechanoelastic model, considering different radii for Co and Ni molecules and different interactions between Co-Co sites and Co-Ni sites. The model reproduced the incomplete transition, with the HS residual fraction at 300 K decreasing with increasing Ni concentration, and provided microscopic snapshots of the systems, showing how the existence of impurities prevented the spreading of Co atoms in the HS state.

Fuzzy‐model‐based robust control of Markov jump nonlinear systems with incomplete transition probabilities and uncertain packet dropouts

AbstractInterval type‐2 fuzzy Markov jump systems (IT2FMJSs) have received much attention because they can well describe complex nonlinear systems with uncertainties and stochastic system mode switching. However, the transition probabilities of fuzzy MJSs (FMJSs) have been assumed to be completely known, limiting real‐world applications of existing results. Different from the previous studies, transition probabilities between system modes switching are partially unknown, and packet dropouts of data transmission are uncertain in this study. Compared with the previous studies, the main advantages of this work are as follows: (1) To analyze stochastic stability and reduce conservatism of existing approaches, a novel Lyapunov function that depends on both system mode and fuzzy basis function is constructed; (2) the existence of a mode‐dependent and fuzzy‐basis‐dependent state feedback controller is revealed; (3) stochastic stability of closed‐loop system with a desired performance is established, and the problem of incomplete transition probabilities and uncertain packet dropouts has been completely addressed. An illustrative example of a robot arm is used to demonstrate the effectiveness and practicality of the proposed control strategy. By virtue of the proposed strategy, the effects of incomplete transition probabilities and uncertain packet dropouts on IT2FMJSs have been completely alleviated.

Dissipative Tracking Control of Nonlinear Markov Jump Systems With Incomplete Transition Probabilities: A Multiple-Event-Triggered Approach

This paper deals with the problem of multiple-event-triggered dissipative tracking control for nonlinear Markov jump systems (MJSs) with incomplete transition probabilities. An interval type-2 (IT2) fuzzy model with partially known transition probability matrix (TPM) is used to capture the underlying nonlinearities, and a hidden Markov model (HMM) with an incomplete conditional probability matrix (CPM) is employed to describe the possible asynchronous phenomenon between the plant and the tracking controller. A multiple-event-triggered methodology involving two adaptive event-triggered schemes (AETS) for the actuator channel and the sensor channel is proposed. By using the Lyapunov and dissipativity theory, sufficient conditions for the desired tracking controller are established in terms of linear matrix inequalities (LMIs). Last, two examples, involving one numerical and one practical model named the Hénon system, are utilized to show the effectiveness of the proposed tracking control algorithm.

The functionality of dream reality in an emigrant text

(E)migration as a kind of initiation stage in the fate of an emigrant, when one’s life seems to start from scratch, typologically defines an emigrant text as a structure of incorporation into the social layers of a new society. This process happens mostly unconsciously and is characterized by certain typological markers, such as reference to mythological and folkloric sources, pretexts from home and world culture, stylizations, carnival, parodies, etc. In this sense, a collection by Ilya Lipkovich, Stan Lipovetsky and Igor Mandel titled “Morpheus and Orpheus. Both Dreams and Spirits: Eyewitness Dreams and Poet’s Commentary” is a model of emigrant writing, broadcasting archetypal conventional imagery systems and allowing a reader to survive the traumatic situation of the still incomplete transition.

Manipulating Electron-Transfer Events in [Fe4 Co4 ] Cubes via a Mixed-Ligand Approach: The Impact of Elastic Frustration.

The engineering of intermolecular interaction is challenging but critical for magnetically switchable molecules. Here, we prepared two cyanide-bridged [Fe4 Co4 ] cube complexes via the alkynyl- and alcohol-functionalized trispyrazoyl capping ligands. The alkynyl-functionalized complex 1 exhibited a thermally-induced incomplete metal-to-metal electron transfer (MMET) behaviour at around 220 K, while the mixed alkynyl/alcohol-functionalized cube of 2 showed a complete and abrupt MMET behaviour at 232 K. Remarkably, both compounds showed a long-lived photo-induced metastable state up to 200 K. The crystallographic study demonstrated that the incomplete transition of 1 was likely due to the possible elastic frustration originating from the competition between the anion-propagated elastic interactions and inter-cluster alkynyl-alkynyl & CH-alkynyl interactions, whereas the latter are eliminated in 2 as a result of the partial substitution by the alcohol-functionalized ligand. Additionally, the introduction of chemically distinguishable cobalt centers within the cube unit of 2 did not lead to a two-step but a one-step transition, possibly because of the strong ferroelastic intramolecular interaction through the cyanide bridges.

Manipulating Electron‐Transfer Events in [Fe4Co4] Cubes via a Mixed‐Ligand Approach: The Impact of Elastic Frustration

AbstractThe engineering of intermolecular interaction is challenging but critical for magnetically switchable molecules. Here, we prepared two cyanide‐bridged [Fe4Co4] cube complexes via the alkynyl‐ and alcohol‐functionalized trispyrazoyl capping ligands. The alkynyl‐functionalized complex 1 exhibited a thermally‐induced incomplete metal‐to‐metal electron transfer (MMET) behaviour at around 220 K, while the mixed alkynyl/alcohol‐functionalized cube of 2 showed a complete and abrupt MMET behaviour at 232 K. Remarkably, both compounds showed a long‐lived photo‐induced metastable state up to 200 K. The crystallographic study demonstrated that the incomplete transition of 1 was likely due to the possible elastic frustration originating from the competition between the anion‐propagated elastic interactions and inter‐cluster alkynyl‐alkynyl & CH‐alkynyl interactions, whereas the latter are eliminated in 2 as a result of the partial substitution by the alcohol‐functionalized ligand. Additionally, the introduction of chemically distinguishable cobalt centers within the cube unit of 2 did not lead to a two‐step but a one‐step transition, possibly because of the strong ferroelastic intramolecular interaction through the cyanide bridges.

Electro-Elastic Modeling of Multi-Step Transitions in Two Elastically Coupled and Sterically Frustrated 1D Spin Crossover Chains

One-dimensional spin crossover (SCO) solids that convert between the low spin (LS) and the high spin (HS) states are widely studied in the literature due to their diverse thermal and optical characteristics which allow obtaining many original behaviors, such as large thermal hysteresis, incomplete spin transitions, as multi-step spin transitions with self-organized states. In the present work, we investigate the thermal behaviors of a system of two elastically coupled 1D mononuclear chains, using the electro-elastic model, by including an elastic frustration in the nearest neighbors (nn) bond length distances of each chain. The chains are made of SCO sites that are coupled elastically through springs with their nn and next-nearest neighbors. The elastic interchain coupling includes diagonal springs, while the nn inter-chain distance is fixed to that of the high spin state. The model is solved using MC simulations, performed on the spin states and the lattice distortions. When we only frustrate the first chain, we found a strong effect on the thermal dependence of the HS fraction of the second chain, which displays an incomplete spin transition with a significantly lowered transition temperature. In the second step, we frustrate both chains by imposing different frustration rates. Here, we demonstrate that for high frustration values, the thermal dependence of the total HS fraction exhibits multi-step spin transitions. The careful examination of the spin state structures in the plateau regions showed the coexistence of special dimerized ferro–antiferro patterns of type LL-HH-LL-HH along the first chain and HH-LL-HH-LL (H=HS and L=LS) along the second one, revealing that the two chains are antiferro-elastically coupled. This type of spatial modulation of the spin state and bond length distances is very attractive because it anticipates the possible existence of periodic structures in 2D lattices, made of alternate 1D SCO strings with HLHLHL structures, coupled in the ferro-like fashion along the interchain direction.

Improved aperiodic sampled-data control for singular Markov jump systems under incomplete transition descriptions

This paper studies the aperiodic sampled-data control problem of singular Markov jump systems under uncertain and unknown transition rates. First, taking into account the system information from x(tk) to x(tk+1), a novel two-sided looped mode-dependent Lyapunov–Krasovskii function (LKF) is constructed, which provides more freedom to test the feasibility of the LMI condition in the criterion. Based on this LKF and an improved integral inequality, a stochastic admissibility condition is given by linear matrix inequalities (LMIs), which is less conservative. Then, by using a lemma of equivalent set, a controller algorithm without equality constraint is proposed by LMIs to ensure the stability of the system. Finally, several examples are provided to verify the validity of the main results.

Protic Amine Carboxylic Acid Ionic Liquids Additives Regulate α-FAPbI3 Phase Transition for High Efficiency Perovskite Solar Cells.

The α-phase formamidinium lead tri-iodide (α-FAPbI3 ) has become the most promising photovoltaic absorber for perovskite solar cells (PSCs) due to its outstanding semiconductor properties and astonishing high efficiency. However, the incomplete crystallization and phase transition of α-FAPbI3 substantially undermine the performance and stability of PSCs. In this work, a series of the protic amine carboxylic acid ion liquids are introduced as the precursor additives to efficiently regulate the crystal growth and phase transition processes of α-FAPbI3 . The MA2 Pb3 I8 ·2DMSO phase is inhibited in annealing process, which remarkably optimizes the phase transition process of α-FAPbI3 . It is noted that the functional groups of carboxyl and ammonium passivate the undercoordinated lead ions, halide vacancies, and organic vacancies, eliminating the deleterious nonradiative recombination. Consequently, the small-area devices incorporated with 2% methylammonium butyrate (MAB) and 1.5% n-butylammonium formate (BAFa) in perovskite show champion efficiencies of 25.10% and 24.52%, respectively. Furthermore, the large-area modules (5cm × 5cm) achieve PCEs of 21.26% and 19.27% for MAB and BAFa additives, indicating the great potential for commercializing large-area PSCs.

Thermal-Driven Guest-Induced Spin Crossover Behavior in 3D Fe(II)-Based Porous Coordination Polymers

3D porous coordination polymers [Fe(bpb)2dca]ClO4·0.5CH3OH·Guest (bpb = 1,4-bis(4-pyridyl)benzene; Guest = chloroform or dichloromethane) (1·3CHCl3 and 1·2.5CH2Cl2, 1 = [Fe(bpb)2dca]ClO4·0.5CH3OH) were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric, magnetic, optical, and calorimetric measurements. The 3D polymer 1·3CHCl3 displays upon cooling an incomplete one-step transition centered at T1/2 ∼ 85 K according to SQUID measurements. The 3D polymer 1·2.5CH2Cl2, however, displays a two-step incomplete spin crossover behavior located between T1/2 ∼ 218 K for the highest transition and T1/2 ∼ 124 K for the lower one. In addition, these materials show different colors due to accommodating chloroform (yellow color) or dichloromethane (orange color) molecules in their cavities. Cryogenic optical microscopy was used to image the spatiotemporal properties of the thermal transition at the scale of a single crystal of both compounds. A gradual transition with a homogeneous color change was detected in 1·3CHCl3 around 90 K, in fair agreement with magnetic data. In contrast, a cooperative hysteretic thermal transition accompanied by delamination and the appearance of well spatially organized microcracks was evidenced in 1·2.5CH2Cl2 around 140 K. The complex two-step spatiotemporal front transformations observed in this system are attributed to the interplay between the SCO and the structural transition. In light of all the above elements, it is thus inferred that host–guest interactions in the crystal cavity can modulate these polymers’ magnetic and optical properties. Such materials can realize the interconversion of high-spin and low-spin states under the stimulation of guest molecules, thus having potential applications as reusable storage for chemical and gas sensors.

Study on Hardness of Heat-Treated CoCrMo Alloy Recycled by Electron Beam Melting.

The hardness of heat (thermally) treated CoCrMo ingots, recycled by electron beam melting and refining (EBMR) of a technogenic CoCrMo material (waste from the dental technology) under different process conditions (temperature and residence time) is examined. The heat treatment consists of two-step heating up to temperatures of 423 K and 1343 K and retention times of 40 and 60 min, respectively. The influence of various loads (0.98 N, 1.96 N, 2.94 N, 4.9 N, and 9.8 N) on the hardness of the CoCrMo alloy, recycled by EBMR, before and after heat treatment is studied. It has been found that regardless of the EBMR process conditions, the obtained samples after heat treatment have similar hardness values (between 494.2 HV and 505.9 HV) and they are significantly lower than the hardness of the specimens before the heat treatment. The highest hardness (600 HV) is measured in the alloy recycled at 1845 K refining temperature for 20 min. This is due to the smaller crystal structure of the resulting alloy and the higher cobalt content. The results obtained show that the heat treatment leads to considerable changes in the microstructure of the CoCrMo ingots recycled by EBMR. With the increase of the e-beam refining temperature, after the heat treatment, the grains' size increases and the grains' shape indicates an incomplete phase transition from γ-fcc to ε-hcp phase. This leads to a slight increase in the hardness of the alloy.

Novel incomplete phase transition from α-Bi2O3 to γ-Bi2O3 constructing dual interfaces contacts with BaTiO3 for highly efficient degradation of antibiotics

Incomplete lattice transition in heterojunction preparation can generate another crystal phase to provide a new transfer channel of electrons and holes for enhancing photocatalytic activity. In this paper, the hydrothermal synthesis of BaTiO3 and α-Bi2O3 composite induced a part of α-Bi2O3 to γ-Bi2O3 lattice transition. Except for α-Bi2O3/BaTiO3 interface, a new BaTiO3/γ-Bi2O3 contact was formed to realize another transfer channel of the charge carriers. The removal efficiencies of norfloxacin and lomefloxacin using the optimal α-Bi2O3/BaTiO3/γ-Bi2O3 sample reached 93% and 95%, much higher than those of the pure phases and the diphasic heterojunction samples. After five times of cycle tests, the photodegradation efficiencies of these two antibiotics were above 90% and 91%, respectively, while the crystal structure of the sample unchanged to exhibit good structure stability. The superoxide radical (O2−), hole, and hydroxyl radicals (OH−) were the main active substances upon the antibiotics degradation. The photocatalytic enhancement mechanism was originated from the formation of a new Z-type energy band according to the surface and interface calculation. Finally, the analysis of mass spectrometry revealed the degradation processes of these two pollutants. These results provided a simple way to obtain efficient double interfaces heterojunction photocatalysts for removing antibiotic pollutants.

Quantization-based tracking control for fuzzy singularly perturbed Markov jump systems with incomplete transition information and packet dropout

Quantization-based tracking control for fuzzy singularly perturbed Markov jump systems with incomplete transition information and packet dropout

Microstructure evolution and shape memory function mechanism of NiTi alloy by electron beam 4D printing

Compared to the traditional additive manufacturing techniques, the electron beam freeform fabrication (EBF3), is carried out in a vacuum atmosphere, indicating its superiority in the manufacturing of element content-sensitive alloy, e.g., NiTi shape memory alloy (NiTi SMA), thus deriving promising application prospects. In this study, with the TC4 alloy was utilized as the substrate, we used EBF3 to fabricate equiatomic Ni50Ti50 SMA successfully. Microstructure evolution, phase transition temperature and structure, mechanical properties, and most significantly, shape memory functional ability after multiple deformations were systematically studied. The deposition was composed of four typical regions: Ni diffusion layer, Ni-Ti reaction layer, Ti diffusion region, and NiTi stable deposited region. The mechanical properties of each region varied from each other. A single reversible martensitic transition occurred during heating and cooling (B2↔B19′). The microstructure of the stable deposited region was B2 austenite phase (Space group: Pm3m), while a small amount of NiTi2 and Ti4Ni2Ox phases precipitated at the grain boundaries. Dislocations tend to form in B2 phase deriving from more slip systems. Because of the incomplete phase transition, tangling and piling up occurred both inside B19′ phase and phase interface during the martensitic transition, which affected the integrity of the B19′ phase and hindered the transition (B19′→B2). As the consequence, the incomplete martensitic transition was also detrimental to the shape memory effect (SME).