Design of optimal fast scanning trajectory for the mechanical scanner of measurement instruments.

This paper focuses on the design of the optimal scanning mode for the family of scanning probe microscopes. Based on different values of the maximum acceleration (deceleration) rate and maximum speed of X- and Y- axes of the mechanical scanner encountered in practice due to different mechanical design and loads, the design procedure of the optimal fast scanning mode is presented, which is found to be sensitive to the specific parameters of the scanning motion. By utilizing the simultaneous motion of the two axes, the fast raster scanning mode proposed can improve the scanning efficiency by 29% when comparing with the conventional raster (CR) scanning mode, if the scanning speeds of both axes are identical. In addition, the optimal fast mode provided by us has no effects on the image accuracy such as image degradation, image distortion when the efficiency is evaluated. No further difficulties are introduced to the control of the mechanical scanner and the data acquisition process. This optimal scanning mode is useful when the response time of the probe is very fast (such as ultrasonic probe in scanning acoustic microscope (SAM)), and the main limitations are due to the mechanical scanner. By applying different loads for both axes, the experiments with different scanning areas and scanning modes are conducted in a self-developed SAM. Experimental results coincide with the theoretical analysis and confirm the validation of our proposed optimal fast scanning mode and its superiority over the CR scanning mode.

The art of electrochemical etching for preparing tungsten probes with controllable tip profile and characteristic parameters.

Using custom made experimental apparatus, the art of electrochemical etching was systematically studied for fabricating micro/nano tungsten probes with controllable tip profiles of exponential, conical, multidiameter, and calabashlike shapes. The characteristic parameters of probe including length, aspect ratio, and tip apex radius could also be well defined. By combining of static and dynamic etching, the conical-shape probe with length up to several millimeters, controllable tip apex radius, and cone angle could be fabricated. In addition, by continuously lifting the tungsten wire up during the electrochemical etching with different speeds and distances, the multidiameter shape probe could be fabricated. Finally by controlling the anodic flow, the multiple "neck-in" could be realized creating a calabashlike probe. The aspect ratio of probes depends on (i) the effective contact time between the surrounding electrolyte and the wire, (ii) the neck-in position of immersed tungsten wire. Under the optimized etching parameters, tungsten probes with a controllable aspect ratio from 20:1 to 450:1, apex radius less than 20 nm, and cone angle smaller than 3° could be achieved. The technique is well suited for the tungsten probe fabrication with a stabilized stylus contour, ultra-sharp apex radius, and high production reproducibility. The art for preparing microprobes will facilitate the application of such microprobes in diverse fields such as dip-pen nanolithography, scanning probe microscopy, micromachining, and biological cellular studies.

[A study on clustering analysis of arrhythmias].

According to the characteristics of ECG analysis, large data quantum, high accuracy demand and real-time, a classified algorithm of arrhythmia based on clustering analysis is presented in this paper. According to "things-of-one-kind-come-together" principle, this algorithm uses the similarities of cases with same kind of heart disease at the same time, includes the factors of the individual difference to analyze arrhythmias by clustering QRS complex waveform and rhythm analysis as the subordinate method. Verified by eight records of MIT-BIR standard heart electricity database, the probability of correct clustering reaches above 90%, which shows that this algorithm can analyze arrhythmias effectively.

Algorithm for Clustering Analysis of ECG Data.

To satisfy the difficult requirements of ECG analysis such as large data volume, high accuracy and real-time, a classification algorithm for arrhythmia based on clustering analysis is developed. According to things-of-one-kind-come-together principle, this algorithm uses the similarity of heart cases of the same category and, at the same time, incorporates the factor of individual differences. It analyzes arrhythmia by clustering QRS complex waveforms and applies rhythm analysis as the subordinate method. Verified by eight records of MIT-BIH arrhythmia standard heart electricity database, the clustering correct rate reaches above 90%, which shows that this algorithm can analyze arrhythmia effectively.

Studies on cognitive and dynamic brain responses to mono-stimulation in human.

Researchers have used primate animals to investigate brain functions at neuron level or even every different level and have achieved a lot progresses and results. However, none of them involved people in their entirety and few studied the dynamics of unfolding brain function as the whole under the life condition of people. Hence people still don't understand well how their cognitive process is completed. We isolated the relatively independent visual system from the complex human body and studied its linkage to cognition. Therefore, by linking stereopsis and cognition this paper studies the cognitive and dynamic response to external mono-stimuli using the electrophysiological method. Investigators directly took part in the entire experimental processes as volunteers. They were able to experience the details of complete cognitive response produced by external stimuli and sense the formation of stable cognition with robustness through personal understanding. The results showed that cognition is a dynamic process of multiple factors. In particular, a new N2 waveform of cognitive characteristics is found to respond to a single stimulus at the advance visual cortex and this N2 waveform is also verified by computing its nonlinear complexity. Differences between dynamic responses to red-blue stereogram pair (RBSGP) and black-white one luminance had response waveforms differed considerably. And the time delay of the peak-to-peak N2 wave in the cognitive dynamic response to the onset of red-blue contrast was greater than the time delay of corresponding N2 peak-to-peak in the response to black-white contrast. Furthermore, our result concurs with the latest advance by A. Anzai in the research of neuron cellular physiology.