Effect Of Imprint Research Articles

On the relationship between imprint and reliability in Hf0.5Zr0.5O2 based ferroelectric random access memory

The detrimental effect of imprint, which can cause misreading problem, has hindered the application of ferroelectric HfO2. In this work, we present results of a comprehensive reliability evaluation of Hf0.5Zr0.5O2-based ferroelectric random access memory. The influence of imprint on the retention and endurance is demonstrated. Furthermore, a solution in circuity is proposed to effectively solve the misreading problem caused by imprint.

Echoes of the Past: State Ownership Imprints on Innovation

The imprint literature has concentrated on the influence of entrepreneurs and political leaders in the start-up phase of organizations on long-term corporate strategy, but little attention has been paid to the enduring impact of the initial shareholders as an important group. We developed a framework in which state ownership imprint, which was left in the start-up stage of the focal firm, have a long-lasting impact on its subsequent innovation strategy through two culture and value mechanism, the bluntness to market competition and the preference for risk aversion. Using a panel data analysis on 925 Chinese private firms from 2008 to 2020, we found that the state ownership imprint decreases the innovation performance of the firms. We further propose that the institutional development in which the firm is embedded weakens the inhibitory effect of the state ownership imprint on innovation by weakening the firm's bluntness to market competition, while the religious cultural environment reinforces the relationship between state ownership imprint and innovation by strengthening firms' risk-averse preferences. Our study contributes to the innovation literature and imprint theory.

Mitigating laser imprint with a foam overcoating

In direct-drive inertial confinement fusion, laser imprint can cause areal density perturbations on the target shell that seed the Rayleigh–Taylor instability and further degrade the implosion. To mitigate the effect of laser imprint, a foam overcoating layer outside the target shell has been suggested to increase the thermal smoothing of the conduction region (between the ablation front and the critical density surface) and mass ablation of the ablation front. In this paper, we use a two-dimensional radiation hydrodynamic code FLASH to investigate the laser imprint mitigation performance and find other physical mechanisms of foam overcoatings. First, radiation ablation dynamically modulates density distribution not only to increase the frequency of the perturbed ablation front oscillation but also to decrease the amplitude of the oscillation. Second, a larger length of the shocked compression region reduces the amplitude of the perturbed shock front oscillation. The areal density perturbations decrease with the decrease in the perturbations of the ablation front and shock front. Based on the abovementioned physical mechanisms, we propose the optimal ranges of foam parameters to mitigate laser imprint with the aid of dimensional analysis: the foam thickness is about two to three times that of the perturbation wavelength, and the foam density is about 1/2–3/2 times that of the critical density.

Sadder but Wiser: The Role of SARS Imprinting and Firms' Recovery During the COVID-19 Pandemic.

Our study provides a new research perspective on firms’ recovery during the COVID-19 pandemic, i.e., can similar events experienced by firms in the past have an imprinting effect on the improvement of firm’s recovery? We focus on firms’ Severe Acute Respiratory Syndromes (SARS) imprints. Based on four quarters of panel data of Chinese A-share listed companies in 2020, our study finds that SARS imprints are positively related to firms’ recovery ability during the COVID-19 pandemic. Meanwhile, if the more severe the SARS pandemic experienced by a firm, the more significant the effect of SARS imprint on the firm’s recovery ability during the COVID-19 pandemic. In addition, the higher the level of digitization of firms during the COVID-19 pandemic, the more it contributed to the enhancing effect of the SARS seal on firm recovery. Our study makes an important theoretical contribution to the recovery literature as well as to imprinting theory, while providing practical guidance for improving the recovery of firms during the COVID-19 pandemic.

Colon cancer patients with mismatch repair deficiency are more likely to present as acute surgical cases

BackgroundThe effect of the genetic imprint on the emergency presentation of colon cancer remains unclear. The disparity between tumours evolving along different carcinogenetic pathways has not been studied systematically. This retrospective multicenter cohort study evaluates the association between mismatch repair status and the risk for acute surgery of colon cancer. Patients and methodsA retrospective multicenter cohort study including in total 870 patients from three different countries. Scandinavian cohort (Finland and Sweden), including a total of 412 patients operated between January 1, 1995 and December 31, 2010, was validated against a cohort from the Czech Republic, including a total of 458 patients, operated between January 1, 2018 and December 31, 2019. The proficiency or deficiency of mismatch repair was determined by immunohistochemistry. Primary outcome was the risk for acute colon cancer surgery given as the Odds Ratio (OR) in the univariable and multivariable analyses. Acute colon cancer surgery was defined as surgery performed during the same hospital admission as when the diagnosis of colon cancer was made. ResultsOf the 870 patients (399 females [46%]) included in the analyses, median age at surgery was 69 [interquartile range, 61–76] years, deficient Mismatch Repair (dMMR) status was found in 190 patients (22%), and 179 patients (21%) underwent acute surgery during the same hospital admission as when the diagnosis of colon cancer was made. In the Scandinavian cohort, a significant association between dMMR status and acute surgery was seen in both the univariable (OR 1.82, 95% CI 1.11–3.02, P = 0.017) and the multivariable (OR = 2.21, 95% CI 1.28–3.95, P = 0.005) analyses. This was confirmed in the Czech validation cohort in both the univariable (OR = 1.94, 95% CI 1.09–3.26, P = 0.022) and the multivariable (OR = 1.77, 95% CI 1.15–3.18, P = 0.021) analyses. ConclusionThis multicenter study reveals a strong association between acute colon cancer surgery and dMMR tumour status.

Producing Masks Amid COVID-19? How A Pandemic Imprint Affects Firm's New Medical Production

We examine how corporate leaders’ prior pandemic experience influences their response to a later and similar pandemic. Drawing on imprinting theory, we argue that corporate leaders that experienced Severe Acute Respiratory Syndrome (SARS) are more likely to be aware of the severity of a new and similar infectious disease (i.e., COVID-19) and so are quicker to respond to COVID-19 by producing personal protective equipment (PPE). We theorize that this imprinting effect can vary in intensity and so the effect of the pandemic imprint is stronger if the corporate leader experienced the SARS during a more susceptible life stage (i.e., early adulthood). Furthermore, a series of environment-triggered processes will also shape the imprinting intensity. Specifically, population mobility from the epicenter and local COVID-19 spread tend to strengthen the effect of a SARS imprint, whereas local quarantine rate and the abundance of local medical resources likely weaken the effect of a SARS imprint. Using a large sample of publicly traded firms in China, we find evidence that mostly supports our theory. Our study contributes to imprinting theory by highlighting how imprinting intensity can vary depending on individual-level susceptibility and environment-level triggered processes. We also contribute to literature on organizational responses to public crises and provide fresh insights on corporate diversification decisions.

Improved physiological performance in grapevine (Vitis viniferaL.) cv. Cabernet Sauvignon facing recurrent drought stress

Background and Aims There is evidence that some species can withstand a stress event better when experienced previously. This capacity could help to increase stress tolerance and resilience under recurrent stresses. To test the effect of a previous season drought imprint on the tolerance to a subsequent drought event, we compared the growth and physiological performance of young cv. Cabernet Sauvignon grapevines growing in a semi-arid zone in Chile. Methods and Results Treatments were single drought (SD; stressed during the second season) and double drought (DD; stressed during the first and second season). During the second season, DD vines budburst earlier, and leaves were smaller. During the drought period, DD showed a higher rate of photosynthesis despite a similar reduction in the stem water potential and stomatal conductance compared to that of SD. Such difference was associated to a higher maximum Rubisco carboxylation rate observed in DD. Conclusions Our results suggest that grapevines exposed to drought are primed for an upcoming second drought event, the priming lasting from one season to the next, involving contrasting growth and physiological performance. Significance of the Study Our study results contribute information to the emerging debate regarding drought-priming effects on the tolerance of grapevines to recurrent drought events.

Computer Modeling on the Effect of the Multistep Nanoimprinting Process in Elastic Deformation Recovery of COC (Cyclic Olefin Copolymer)

The effect of the multistep imprint in elastic deformation recovery was studied numerically with more than one roll and different depth ratios. As well as effect hold-on time on the elastic deformation recovery of polymer Cyclic Olefin Copolymer (COC) material was studied using Generalized Maxwell (GM) constitutive model and their parameters in finite element simulation software of ABAQUS were presented. Firstly, the modified Genetic Algorithm (GA) was employed to obtain a Prony series of the viscoelastic model in terms of experimental data of the complex modulus for COC. To evaluate the elastic recovery of the microstructure, the cross-sectional area of micro-channel before and after hot-imprinting was computed and compared numerically. The simulated results were analysed and clearly showed an improvement in the elastic recovery rate of the microstructure area as the multi-step of rolling was employed.

Long-duration planar direct-drive hydrodynamics experiments on the NIF

The advent of high-power lasers facilities such as the National Ignition Facility (NIF) and the laser megajoule provide unique platforms to study the physics of turbulent mixing flows in high energy density plasmas. We report here on the commissioning of a novel planar direct-drive platform on the NIF, which allows the acceleration of targets during 30 ns. Planar plastic samples were directly irradiated by 300–450 kJ of UV laser light (351 nm) and a very good planarity of the laser drive is demonstrated. No detrimental effect of imprint is observed in the case of these thick plastic targets (300 μm), which is beneficial for future academic experiments requesting similar irradiation conditions. The long-duration direct-drive (DD) platform is thereafter harnessed to study the ablative Rayleigh–Taylor instability (RTI) in DD. The growth of two-dimensional pre-imposed perturbations is quantified through time-resolved face-on x-ray radiography and used as a benchmark for radiative hydrocode simulations. The ablative RTI is then quantified in its highly nonlinear stage starting from intentionally large 3D imprinted broadband modulations. Two generations of bubble mergers is observed for the first time in DD, as a result of the unprecedented long laser acceleration.

The Effect of Imprint and Disturb on Switching Process Based on Poly(vinylidene fluoride-trifluoroethylene) Copolymer Thin Films

The simultaneous effect of disturbance and imprint on the polarization switching behaviors of ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) thin films has been investigated. The results show that the switching characteristics are affected obviously by the imprint as well as the disturbing process. The switching characteristics are well analyzed using the “single read-dual integration” pulse protocol. It is found that the decrease of M-value (“M-value” model is defined as the differences between a switching and a non-switching polarization) with disturb is much faster than that of the pure imprint both before and after fatigue. This result is useful for the design of the related ferroelectric devices.

Laser imprint reduction for the critical-density foam buffered target driven by a relatively strong foot pulse at early stage of laser implosions

In order to reduce the effect of laser imprint in direct-drive ignition scheme a low-density foam buffered target has been proposed. This target is driven by a laser pulse with a low-intensity foot at the early stage of implosion, which heats the foam and elongates the thermal conduction zone between the laser absorption region and ablation front, increasing the thermal smoothing effect. In this paper, a relatively strong foot pulse is adopted to irradiate the critical-density foam buffered target. The stronger foot, near 1 × 1014 W/cm2, is able to drive a radiative shock in the low-density foam, which helps smooth the shock and further reduce the effect of laser imprint. The radiative shock also forms a double ablation front structure between the two ablation fronts to further stabilize the hydrodynamics, achieving the similar results to a target with a high-Z dopant in the ablator. 2D analysis shows that for the critical-density foam buffered target irradiated by the strong foot pulse, the laser imprint can be reduced due to the radiative shock in the foam and an increased thermal smoothing effect. It seems viable for the critical-density foam buffered target to be driven by a relatively strong foot pulse with the goal of reducing the laser imprint and achieving better implosion symmetry in the direct-drive laser fusion.

Quantifying electronic charge trap states and the effect of imprint on ferroelectric poly(vinylidene fluoride-trifluoroethylene) thin films

Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] thin films have been extensively studied for their ferroelectric properties and are a promising material for sensing and memory applications. Imprint, the time-dependent resistance to polarization reversal, is a key material property that limits applications and is poorly understood. We have used a fast ramp rate thermally stimulated current (FR-TSC) technique to investigate the proposed link between imprint time and filling of charge trap states, and to characterize these traps in an appropriate time-frame. Thin films of P(VDF-TrFE) on oxidized Si substrates were characterized following controlled initialization, fatigue, polarization, and imprint. Traps were allowed to fill during room temperature imprint for times from 1 to 104 s. Remaining unfilled traps were subsequently filled and quantified by FR-TSC temperature cycling from 20 to 100 °C at 1 K/s. Results confirm that charge trap filling occurs both with time, under isothermal conditions, as well as with increasing temperature. The rate of charge accumulation induced by FR-TSC exhibits the same logarithmic dependence with time as the experimentally measured imprint voltage; this strongly suggests a direct link between these trapped charges and the imprint field. Furthermore, measurements of the switching speed in post FR-TSC films were found to be independent of the imprint time, confirming that thermal cycling brought all samples to a common final state. These results provide further understanding of the polarization dynamics and materials interactions affecting the ferroelectric properties of P(VDF-TrFE).

Formulization of long-time domain switching around the coercive field from imprint measurements on ferroelectric thin films

The time interval for the completion of slow polarization reversal in ferroelectric thin films measured in the order of magnitude of 10−9–100s is broadened by more than two decades as the applied field approaches the coercive field of domain switching. The domain-switching kinetics is conjectured to change from the classical Kolmogorov–Avrami–Ishibashi (KAI) model at high fields to nucleation-limited-switching (NLS) model at low fields. However, the true voltage drop across the film from the real-time measurement of the oscilloscope remains constant at a coercive voltage Vc during polarization reversal irrespective of the applied voltage. Therefore, the above high-field assumption for KAI does not exist. From our measurements, a long-time effect of imprint can occur for any slow processes of physical phenomena, even if the imprint field is very weak. The imprinted Vc can be estimated either from the voltage shift in the curve of switched polarization versus the applied voltage or directly from the height variation in domain-switching current plateau after an imprint voltage Vimp for time timp (1μs<timp<10ms). Vc reduces continually with timp under Vimp>0 to exhibit a linear time dependence in a logarithmic scale above an initial time on the order of 1.0μs, even if under Vimp<Vc, which foretells the possibility of the initial unswitched domains with negative polarizations to switch into positive states with the prolonged imprint time under a positive voltage of Vimp. After formulation of the Vc-timp dependence under Vimp according to imprint principles, we derive the time evolution of slow polarization reversal without evoking KAI and NLS approaches once the Vc distribution is obtained for a genuine thin film. The spectrum derivation is completely comparable to experimental measurements, which suggests the common physics between imprint and long-time domain switching of ferroelectric thin films.

Effect of imprint on operation and reliability of ferroelectric random access memory (FeRAM)

The effect of the imprint on the operation of the ferroelectric random access memory (FeRAM) was estimated by a quasitheoretical model, including the hysteresis shift along the voltage axis and the depolarization induced by the hysteresis shift. Based on the experimental data of the imprint up to 90 days, the hysteresis shift and the depolarization are expressed by a stretched exponential equation as the aging time, and a hyperbolic tangent as the shifted voltage, respectively. Using this model, nonlinear phenomena of bit-line voltage change with the aging time is successfully predicted, and the aging reliability for two transistor and two capacitor (2T/2C) cell architecture with the imprinted capacitors is estimated for the first time. This technique is applied to the evaluation of aging reliability for the Pb(Zr,Ti)O/sub 3/ and (Pb,La)(Zr,Ti)O/sub 3/ capacitors, revealing that the latter has higher reliability than the former.

Simulations of laser imprint for Nova experiments and for ignition capsules

In direct drive inertial confinement fusion (ICF), nonuniformities in laser illumination seed ripples at the ablation front in a process called “imprint.” These nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser [Campbell et al., Rev. Sci. Instrum. 57, 2101 (1986)] examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I≅1013 W/cm2. The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of ∼10 nm rms. Modulation growth was examined using the Haan [Phys. Rev. A 39, 5812 (1989)] model, with linear growth factors as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two-dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved.

Metamorphic features in North American massive sulfide deposits

Many massive sulfide deposits in North America show textures and structures that are deformational in origin. These features have been superimposed on original mineralogical ones to the extent that in many deposits the essential characteristics necessary to elucidate the conditions of primary genesis no longer exist. The massive sulfide deposits have been metamorphosed with their walls, thereby destroying much of the evidence of wall-rock alteration, if it existed at all.Thus, characteristically a metamorphosed ore shows a granoblastic texture; complex and paragenetically inconsistent grain-boundary relationships; the porphyroblastic growth of some minerals, and the re-equilibration of others under metamorphic conditions; and the migration of minerals like chalcopyrite in a stress-field.The least altered deposits studied by the writer are the Kam Kotia Mine, Ontario, and the Anacon Mine, N. B. Those showing the greatest effect of a metamorphic imprint are Heath Steele, N. B., but especially the Appalachian pyritic deposits extending from Maine to Ducktown. On the basis of a literature survey the writer proposes that the Horne Mine, Quebec, and the Thomson Lake nickel deposits in Manitoba also predate the last period of metamorphism.Concerning New Brunswick ores, the writer concludes from his work and the review of existing data that: (1) the ores were fine-grained originally; (2) one cannot deduce the sequential deposition of minerals, or introduction of metals, from a study of their textures; (3) the O 16 /O 18 equilibrium temperature (515 degrees C) on a quartz-magnetite pair from the country rock indicates the possibility of fairly high temperatures during the regional metamorphic episode; (4) the ores may be of Ordovician age; (5) the ores may have been deposited, or dumped, under slight lithostatic or hydrostatic load, forming replacements in consolidated or unconsolidated sediments.