Effects of Predeformation on the Reverse Martensitic Transformation of TiNi Shape Memory Alloy

DSC was used to study the effects of predeformation on the reverse martensitic transformation of near-equiatomic TiNi alloy. Both the start temperature As and the finish temperature Af of the reverse transformation increased with increasing degree of predeformation, but the algebraic difference between As and Af decreased with increasing predeformation until it reached a minimum value, then remained unchanged with further deformation. Transformation heat also increased with increasing predeformation until it reached a maximum value, then decreased with further predeformation. All the phenomena above were considered to be closely related with the release of elastic strain energy during predeformation.

MICROSTRUCTURE AND REVERSE SHAPE MEMORY EFFECT IN A Cu-Zn-Al ALLOY

The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint stress.The widespread propagation of bainite was confirmed to be the diffusion controlled shear process by the parabolic configuration of side interface of bainite plate and the twisting of intersected bainite plates.

A Modified Lattice Model of the Reversible Effect of Axial Strain on the Critical Current of Polycrystalline REBa2Cu3O7-δ Films

The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.

THE FAILURE MECHANISM OF REVERSE SHAPE MEMORYEFFECT IN A Cu-BASE ALLOY

The interior structural evolution accompanying reverse shape memory effect (RSMEin a Cu-Zn-Al alloy was studied by means of transmission electron microscopy. It was found that RSME is closely related to bainitic transformation in this alloy during the isothermal reaction at moderate temperatures. At a given temperature and a certain external constraint stress, the shape memory effect depends mainly on the aging time.During the early stage, the shape memory effect enhances with the increase of reactiotn time. Then it will decrease gradually apon further aging. If the alloy is overaged, the stacking faults of bainite will disappear gradually by the motion of partial dislocations through which long range diffusion of solute atoms takes place, giving rise to the deterioration of RSME. When all the bainite transforms to α phase, RSME will lose completely.

Axial Shock in a Cylindrical Plasma with Current

Hugoniot relations of a two-dimensional axial shock with current and magnetic field in a cylindrical shock tube were investigated by a numerical method. The radial profiles of the magnetic field, electric current, pressures, flow velocities and temperatures between the up- and down-stream radial force-balanced plasma of the shock were revealed by numerical analysis. It is clearly found that the axial shock can lead to two effects： one is an inverse skin effect （i.e., the current density rises towards the center of the conductor）, the another is a reversed current effect which occurs near the edge and about a half radius. It is also found that the radial gradient of pressure, density and temperature all become very large near the center due to the axial shock.

The Strong Cooperativity of Dioxygen Binding by Dicobalt(II) Diporphyrin Compounds in Nonaqueous Solution at Room Temperature

Thermodynamic data were determined for the reversible binding of O 2 to two compounds of dicobalt(II) di(meso tetra phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co 2PP 8 and Co 2PP 4) in N,N dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half oxygenation ( P 1/2 ) and Hill coefficient ( n ) at 298 K were determined as follows: P 1/2 =54.2 kPa, n =2.0 for Co 2PP 8 and P 1/2 =6.8 kPa, n =1.8 for Co 2PP 4,respectively. The rate equations of reversible oxygen binding by Co 2PP 8 were determined and the reaction path was proposed. The results of thermodynamic and kinetic studies indicate that there exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes formed in the solutions are of superoxo (Co O - 2) type.

Effects of In-video Questions and Feedback on Learning Performance

The eye-tracking technology was used in this study to investigate the effects of embedded questions and feedback in instructional videos on learning performance and attention allocation and whether an expertise reversal effect existed.The experiment involved 49 learners with high-level prior knowledge and 45 ones with low-level prior knowledge from a university.Meanwhile,they learned instructional videos with no embedded feedback,embedded questions without feedback and embedded questions with feedback.Findings from the experiment showed that the instructional videos with embedded questions but without feedback not only improved the participants’attention but also enhanced their learning performance.Furthermore,there was an expertise reversal effect on the learning performance whereby instructional videos with embedded questions but without feedback improved the learning performance of learners with low-level prior knowledge,but not those with high-level prior knowledge.

Fixing an illusion–an empirical assessment of correction methods for the terrain reversal effect in satellite images

Identifying land forms and land cover classes are important tasks in image interpretation.Sometimes,a phenomenon called terrain reversal effect(TRE)causes an inverted perception of 3D forms.When this inversion occurs,valleys appear as ridges and vice versa.While the TRE can severely impair the ability to identify 3D land forms,‘correcting’for the TRE in imagery can introduce new problems.Importantly,one of most commonly-proposed methods–shaded relief map(SRM)overlay–appears to impair the ability to identify land cover classes.In this paper,we report a comparative empirical evaluation of an SRM overlay solution,and its‘enhanced’versions supported by various other cues(stereopsis,motion,labels).In response to the different solutions,we measure the effectiveness,efficiency,confidence and preferences of our participants in land form and land cover identification tasks.All examined methods significantly improve the ability to detect land forms accurately,but they also impair the ability to identify the land cover classes to different degrees.Additionally,participants’visualization preferences contradict their performance with them,calling for reflection on the visual effects of the applied correction methods.Based on the study,recommendations concerning the correction of the TRE are drawn,and gaps are identified.

Simulation analysis of heavy-ion-induced single-event response for nanoscale bulk-Si FinFETs and conventional planar devices

FinFET technologies are becoming the mainstream process as technology scales down.Based on 28-nm bulk-Si FinFETs and

A 320 mV,6 kb subthreshold 10T SRAM employing voltage lowering techniques

This paper presents a 6 kb SRAM that uses a novel 10T cell to achieve a minimum operating voltage of 320 mV in a 130 nm CMOS process. A number of low power circuit techniques are included to enable the proposed SRAM to operate in the subthreshold region. The reverse short channel effect and the reverse narrow channel effect are utilized to improve the performance of the SRAM. A novel subthreshold pulse generation circuit produces an ideal pulse to make read operation stable. A floating write bit-line effectively reduces the standby leakage consumption. Finally, a short read bit-line makes the read operation fast and energy-saving. Measurements indicate that these techniques are effective, the SRAM can operate at 800 kHz and consume 1.94/zW at its lowest voltage （320 mV）.

Near infrared light triggered nitric oxide releasing platform based on upconversion nanoparticles for synergistic therapy of cancer stem-like cells

Near infrared(NIR) light-driven nitric oxide(NO) release nano-platform based on upconversion nanoparticles(UCNPs) and light sensitive NO precursor Roussin's black salt(RBS) was fabricated to generate NO upon 808 nm irradiation. The application of 808 nm laser as the excitation source could achieve better penetration depth and avoid overheating problem. The combination of UCNPs and RBS could realize the on-demand release of NO at desired time and location by simply controlling the output of NIR laser.Cellular uptake results showed that more nanoparticles were internalized in cancer stem-like cells(CSCs)rather than non-CSCs. Therefore, a synergistic cancer therapy strategy to eradicate both CSCs and nonCSCs simultaneously was developed. Traditional chemo-drug could inhibit non-CSCs but has low killing efficiency in CSCs. However, we found that the combination of NO and chemotherapy could efficiently inhibit CSCs in bulk cells, including inhibiting mammosphere formation ability, decreasing CD44^+/CD24^- subpopulation and reducing tumorigenic ability. The mechanism studies confirmed that NO could not only induce apoptosis but also increase drug sensitivity by declining drug efflux in CSCs. This UCNPsbased platform may provide a new combinatorial strategy of NO and chemotherapy to improve cancer treatment.

A site-oriented nanosystem for active transcellular chemo-immunotherapy to prevent tumor growth and metastasis

Immunotherapy has shown promising potential in cancer therapy;however, poor delivery by nanocarriers and insufficient immune response in tumors have severely impeded its clinical application. To overcome these disadvantages, a site-specific and active transcellular drug delivery system was developed herein for chemotherapyenhanced immunotherapy. When arriving at the tumor site,the matrix metallopeptidase 2(MMP2)-responsive shell detached from the nanosystem, releasing positively charged cores. The cationic surface of the inner cores induced adsorption-meditated transcytosis, which facilitated transendothelial transportation and transcellular drug delivery into distal tumor cells. PD-L1 antibody and chemotherapeutic drugs were loaded in the outer layer and inner cores of the nanosystem, respectively, to be precisely delivered to target sites, thereby achieving synchronized delivery and siteoriented release of different anticancer agents. PD-L1 antibody released in the tumor microenvironment effectively blocked the binding of PD-L1 to its receptors on the T cell surface. Oxaliplatin and indoximod co-delivered in the cationic cores can induce immunogenic cell death and attenuate the immunosuppressive effect throughout the tumor tissues,recruiting a large amount of T cells and further enhancing the immunotherapy. The resulting synergistic antitumor response could not only efficiently inhibit the growth of primary tumors, but also help prevent metastasis of primary tumor to distant sites. This study offers a novel nano-enabled strategy for chemo-immunotherapy in immunosuppressive tumors.

Reversible Plasticity Shape Memory Effect in SEBS/Crystallizable Paraffin: Influence of Paraffin Content

Polymers with reversible plasticity shape memory effect(RPSME)have attracted considerable attention due to their simple programming and large deformation.However,the exact mechanisms of RPSME are still not thoroughly understood.In this work,the RPSME of SEBS/crystallizable paraffin was investigated by comparatively analyzing the performances and microstructures of samples with different paraffin content.It was found the shape fixing ratios(Rfs)of samples increased with the paraffin content,and interestingly,a significant improvement in Rf was observed when the paraffin content exceeded 60 wt%.Tensile test results showed that the deformation characteristics of samples changed from elastic to plastic as the paraffin content increased above 60 wt%.By exploring the crystallization behaviors of paraffin in various SEBS/paraffin samples,it was revealed that the microstructures of SEBS/paraffin were different when the paraffin content was below 50 wt%and above 60 wt%.In samples with low paraffin content(below 50 wt%),nearly all paraffin was co-crystallized with ethylene-co-butylene(EB)chains and its crystallization was severely restricted;while in samples with high paraffin content(above 60 wt%),“excess”paraffin appeared and this part of paraffin crystallized on the template of the EB/paraffin co-crystals,which might be responsible for the elastic-to-plastic transition and the sharp increase in Rf.Based on the above results,a possible structural model was proposed to explain the exact mechanism of RPSME in SEBS/paraffin.

Effect of Fe concentration on the nonlinear refraction and reverse saturable absorption in ferroelectric X-cut LiNbO_3 crystal

In this Letter, the effects of the iron （Fe） dopant concentration on the nonlinear optical properties of iron-doped ferroelectric X-cut LiNbO3 crystals plates are studied by using the Z-scan technique with a cw laser at the wave- length of 532 nm. The amount of iron in the compound is varied from 0 to 0.15 mol%. Measurements of nonlinear refractive index n2 and the nonlinear absorption coefficient β are determined. The sign of the nonlinear refractive index is found to be negative and the magnitude is on the order of 10-s cm2/W. This nonlinear effect increases as the concentration increases from 0 to 0.15 mol%. A good linear relationship is obtained between nonlinear refractive index, nonlinear absorption coefficient, and concentration.