Staircase Pulse Research Articles

An Optimized Fast Stair-case Set Pulse with Variable Width for Phase Change Random Access Memory

Phase change random access memory tend to provide the write speed close to that of DRAM to expand applications in stand-alone and embedded filed. The period of set operation is the key parameter to determine the write speed. In this paper, a method for optimizing each step width of a stair-case pulse is proposed. The width of each step can be adjusted according to the cell percentage for set current acquired from the lowest resistance point in the Resistance-Current curve. This method can solve the heating inconsistency problem of set operation and is beneficial to speed and set resistance distribution. The experiment results are gathered across a 16 Kb blocks of a 4 Mb PCRAM chip with 40 nm CMOS process. The resulting optimized stair-case set pulse speed is less than 100 ns.

Subsequent set pulse impacts on set resistance distribution of phase change memory

Subsequent set pulse in stair-case pulse, which is used to control the cooling process of phase change memory (PCM), is still not enough in-depth exploration. A detailed investigation that the effect of subsequent set pulse on the set resistance distribution is presented. The improper subsequent set pulse amplitude and duration cause the cooling process of phase change material to deviate from the crystallization requirements, which leads to poor set resistance distribution. The optimal cooling current (OCC) can generate a linear decrease of the temperature, it is necessary for optimum crystallization. The thermal simulation suggests that the optimal subsequent set pulse has a similar temperature evolution to OCC. Hence the optimal subsequent set pulse enables minimum resistance, and its amplitudes are from 400 to 80 μA and each pulse duration is 50 ns.

Fabrication of conducting polymer/noble metal nanocomposite modified electrodes for glucose, ascorbic acid and tyrosine detection and its application to identify the marked ages of rice wines

In previous studies, conductive polymers (CPs)/noble metal nanoparticles (NMNPs) composite materials modified electrodes were always applied to distinguish the trace amounts of specific analytes in complex liquid mixtures. In this paper, polymer sulfanilic acid (PABSA)/AuNPs/glassy carbon electrode (GCE), polymer acid chrome blue K (PACBK)/AuNPs/GCE and polymer aspartic acid (PASP)/PtNPs/GCE were fabricated for the identification of the wine age of rice wines with pattern recognitions. The sensitivity of those modified electrodes was exhibited by cyclic voltammetry, and the parameters of electrochemical behaviors was optimized and confirmed gradually. The original responses were recorded by chronoamperometry with multi-frequency rectangle pulse voltammetry and multi-frequency staircase pulse voltammetry, and the feature data correlated with the wine age were extracted from original responses by ‘area method’. Based on the feature data, principal component analysis (PCA, unsupervised method), locality preserving projections (LPP, semi-supervised method) and differential financial analysis (DFA, supervised method) were applied for the classification of rice wine samples with different marked age, and DFA exhibited the most clear result; least squares support vector machines (LSSVM) and library for support vector machines (LIBSVM) were applied for the prediction of the wine ages, and LIBSVM worked better than LSSVM, the correlations based on the training and testing dataset were R2=0.9999 and R2=0.9998, respectively. In conclusion, the CPs/NMNPs/GCEs with pattern recognitions were powerful tools to identify the marked ages of rice wines.

Nickel and copper foam electrodes modified with graphene or carbon nanotubes for electrochemical identification of Chinese rice wines

The authors describe the application of two types of metallic foams modified with either graphene (GR) or carbon nanotubes (CNTs) as voltammetric electrodes in order to discriminate rice wines of different age and brand. Two types of bare metallic foams (bare Ni and Cu foam electrodes) were combined with GR or CNTs to give four types of modified metallic foams, referred to as GR/Ni, GR/Cu, CNT/Ni, and CNT/Cu foam electrodes. Cyclic voltammetry was applied to study the effects of GR and CNTs on the response of the electrodes. Multifrequency rectangle pulse voltammetry and multifrequency staircase pulse voltammetry were applied to generate potential waveforms, and chronoamperometric curves were recorded. Principal component analysis (PCA) allowed a classification of the rice wines, and characteristic regular distributions were identified in the PCA plots. Support vector machines (SVM) were found to perform better than partial least squares regression in predicting ages and brands of the rice wines in that all fit correlation coefficients were >0.9930. The SVM based leave-one-out cross-validation method proved to be the most powerful regression tool. The six types of foam electrodes perform very well in the classification and prediction of rice wines of different ages and brands.

Monitoring the fermentation, post-ripeness and storage processes of set yogurt using voltammetric electronic tongue

A voltammetric electronic tongue (VE-tongue) was self-developed to monitor the fermentation, post-ripeness and storage processes of set yogurt. Multifrequency rectangular pulse voltammetry (MRPV) and multifrequency staircase pulse voltammetry (MSPV) were applied as potential waveforms, and the ‘area method’ was applied to extract feature data from the original responses. The ANOVA analysis was performed to evaluate the effects of electrodes and potential waveforms on the electrochemical responses, and the visualization of the Pearson Correlation Coefficient was performed to analyze the correlations among each combination of electrode and potential waveform. Discriminant function analysis worked better than principal component analysis based on the fusion data of MRPV- and MSPV-area data in classifying set yogurts in the stages of fermentation, post-ripeness and storage, respectively. VE-tongue with support vector machine (SVM) worked efficiently and stably in predicting the fermentation time, pH and viscosity of samples during the fermentation process; while the use of VE-tongue and partial least squares regression (PLSR) should be the first choice for the prediction work during the post-ripeness and storage processes. According to the classification and prediction results, the VE-tongue with different potential waveforms was proved a promising tool for monitoring the fermentation, post-ripeness and storage processes of set yogurt.

Recrystallization process controlled by staircase pulse in phase change memory

In this study, we investigate the recrystallization process in phase-change memory by applying staircase pulses. The controlled recrystallization process is expected to be applied to freely achievable multilevel storage. Simulation results exhibit that the phase change material is heated above its melting point during the first subpulse of the staircase pulse and then annealing temperature can be controlled by varying amplitude of the second subpulse. This implies that the recrystallization region is controllable by applying staircase pulses. V-shaped resistance change vs. the amplitude of the second subpulse, which is caused by the growth and the shrinkage of recrystallized region, is obtained at each width of second subpulse.

Evaluation of varieties of set yogurts and their physical properties using a voltammetric electronic tongue based on various potential waveforms

Abstract A voltammetric electronic tongue (VE-tongue) was self-developed to discriminate six categories of set yogurt. The VE-tongue was comprised of four working electrodes (gold, silver, platinum, and palladium), and three potential waveforms: multifrequency hackle pulse voltammetry (MHPV), multifrequency rectangle pulse voltammetry (MRPV) and multifrequency staircase pulse voltammetry (MSPV) was applied to working electrodes in the study. All the three potential waveforms were composed of three frequencies of 1 Hz, 10 Hz, and 100 Hz (the corresponding step length of each frequency of LAPV is 1 s, 0.1 s, and 0.01 s, respectively), the total areas under the corresponding curves obtained in three frequencies were performed as the characteristic values, which were analyzed by principal component analysis (PCA) and discriminant function analysis (DFA) for category classification. The VE-tongue based on MSPV with PCA presented the best separation ability in classifying the six categories of set yogurt. All the samples were separated clearly, furthermore, the yogurt samples produced by MengNiu Company also could be separated clearly from samples produced by non-MengNiu Company. Partial least squares regression (PLSR) was used for category forecast. The total areas obtained by VE-tongue based on MSPV were taken for PLSR analysis, and the PLSR showed a good prediction result (the correlation coefficient between measured and predicted values of the training set and testing set was R2 = 0.9675 and R2 = 0.9409, respectively). Additionally, the following physical properties of yogurt samples were also determined: surface stress and viscidity. Through the use of PLSR analysis, it was found a rather good correlation between surface stress and the voltammetric data, and the correlation coefficient between measured and predicted values of the training set and testing set was R2 = 0.9079 and R2 = 0.8726, respectively. PLSR performed badly for the prediction of viscidity, and the correlation coefficient between measured and predicted values of the testing set was R2 = 0.7508. These results suggest that this simple VE-tongue could be useful for the undemanding qualitative or quantitative evaluation of categories and surface stress of set yogurt samples.

Monitoring of quality and storage time of unsealed pasteurized milk by voltammetric electronic tongue

A voltammetric electronic tongue (VE-tongue) was self-developed and applied to monitor the quality and storage time of unsealed pasteurized milk. The VE-tongue comprised four working electrodes: gold, silver, platinum, and palladium electrode. Two potential waveforms: Multi-frequency rectangle pulse voltammetry (MRPV) and multi-frequency staircase pulse voltammetry (MSPV) were applied to working electrodes in the study, and both of MRPV and MSPV consisted of three frequency segments: 1Hz, 10Hz, and 100Hz. The total areas under the corresponding curves obtained by VE-tongue in the three frequencies were applied as characteristic data, which were evaluated by the principal component analysis (PCA) and cluster analysis (CA). The results of PCA and CA indicate that the milk samples of different storage time could be successfully classified by the VE-tongue based on MRPV and MSPV, respectively. Combining the areas obtained by the VE-tongue based on MRPV and MSPV, the classification results of PCA and CA were improved evidently. The total bacterial count, acidity and viscosity of the milk samples were also measured during the storage, and those physicochemical characteristics showed regular configuration in PCA and CA plots. Furthermore, the total bacterial count and viscosity properties were predicted by partial least squares regression (PLSR) and least squares-support vector machines (LS-SVM), and the combination of the areas obtained by the VE-tongue based on the MRPV and MSPV were applied as the input data of PLSR and LS-SVM. Both the prediction techniques performed well in predicting viscosity and total bacterial count, and the prediction results of LS-SVM were better than that of PLSR. Those results demonstrate that the VE-tongue could be applied to monitor the quality storage time of unsealed pasteurized milk.

Staircase pulse voltammetry

AbstractThe faradaic current of interest can often be obscured by some extraneous current. A new method called staircase pulse voltammetry (SPV), with which involving a potential pulse is superimposed on a staircase, is used for removing the double‐layer charging current This paper presents the theoretical consideration and the experimental evidence of this method for a simple reversible system and a catalytic process. The parameters affecting currents are also discussed. Experimental verifications are in agreement with the theories.

Current-Voltage Curves for Plant Membrane Studies: A Critical Analysis of the Method

The evolution of the steady-state current-voltage (I/V) method is followed to its present sophistication of bipolar staircase. When applied to Chara plasmalemma the resultant I/V characteristics vary enormously depending on the physiological state of the membrane (which is, in turn, dictated by the outside conditions). This variety of response makes formulation of ‘correct’, that is artefact-free, I/V technique quite a challenge. The time-dependence of the clamp current in each electrophysiological state is different and this must be taken into consideration when steady-state I/V is investigated. Clamping of the plasmalemma alone is also necessary, as under some conditions the conductance of the two membranes becomes similar and the effects of the tonoplast can no longer be neglected when both membranes are clamped in series. The data obtained by point clamping and space clamping are compared. The use of bipolar staircase introduces more subtle artifacts: the I/V profiles can be severely misinterpreted due to transient conductance changes arising from the excitation or the outward and inward rectifier currents. The excitation can be blocked by temporary exposure to lanthanum ion, but the concentration must be carefully chosen. It is necessary to optimize the staircase parameters to allow the rectifier currents to return to resting level before the next staircase pulse. Finally, brief comparison of the Chara I/Vprofile to that of other cells is included and the relevance to patch clamp studies discussed.

Extension of Mueller's theory on optimum pulse shaping for data transmission

A novel theory for finding the optimum pulse waveform for data transmission is presented. It leads to a finite-duration pulse with zero intersymbol interference and maximum energy concentration in a given bandwidth. The synthesised pulse is piecewise linear rather than the staircase pulse previously discussed in the literature.

A Modulated Fast Bump for the CPS Continuous Transfer

The CERN SPS receives beam from the CPS by the continuous transfer process. The paper outlines the role of a modulated fast bump in this process and describes the magnets and pulse generators which produce it. Particular attention is given to the high voltage staircase pulse generator which determines the degree of modulation of the bump. Operating experience since the start of SPS commissioning is reported.