The scanning tunneling microscope is proposed as a method to measure forces as small as 10 N. As one application for this concept, we The SP has much in common with the STM. The tip in the STM and the stylus in the SP are both used to scan the surface, sense the variations of the sample, and generate three-dimensional images. The stylus in the profilometer is carried by a cantilever beam and it rides on the sample surface. This means that a rough surface can be plastically deformed. " The radius of this stylus is about 1 p, m, and the loading force extends from 10 to 10 N. ' The spring in the AFM is a critical component. %e need the maximum deflection for a given force. This requires a spring that is as soft as possible. At the same time a stiff spring with high resonant frequency is necessary in order to minimize the sensitivity to vibrational noise from the building near 100 Hz. The resonant frequency, fo, of the spring system is given by f0= (I/2sr)(k/nto)', where k is the spring constant and ttto is the effective mass that loads the spring.This relation suggests a simple way out of our dilemma. As we decrease k to soften the spring we must also decrease mo to keep the ratio k/mo large. The limiting case, illustrated in Fig. 1, is but a single atom adsorbed at site A in the gap of an STM. It has its own mass and an effective k that comes from the coupling to neighboring atoms.The mass of the spring in manmade structures can be quite small but eventually microfabrication'4 will be employed to fabricate a spring with a mass less than 10 '0 kg and a resonant frequency greater than 2 kHz. Displacements of 10 A can be measured with the STM when the tunneling gap is modulated. The force

This paper presents a comparison study between 10 automatic and six interactive methods for liver segmentation from contrast-enhanced CT images. It is based on results from the "MICCAI 2007 Grand Challenge" workshop, where 16 teams evaluated their algorithms on a common database. A collection of 20 clinical images with reference segmentations was provided to train and tune algorithms in advance. Participants were also allowed to use additional proprietary training data for that purpose. All teams then had to apply their methods to 10 test datasets and submit the obtained results. Employed algorithms include statistical shape models, atlas registration, level-sets, graph-cuts and rule-based systems. All results were compared to reference segmentations five error measures that highlight different aspects of segmentation accuracy. All measures were combined according to a specific scoring system relating the obtained values to human expert variability. In general, interactive methods reached higher average scores than automatic approaches and featured a better consistency of segmentation quality. However, the best automatic methods (mainly based on statistical shape models with some additional free deformation) could compete well on the majority of test images. The study provides an insight in performance of different segmentation approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

We report on the first successful tunneling experiment with an externally and reproducibly adjustable vacuum gap. The observation of vacuum tunneling is established by the exponential dependence of the tunneling resistance on the width of the gap. The experimental setup allows for simultaneous investigation and treatment of the tunnel electrode surfaces.

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We present a new scanning-probe-based data-storage concept called the "millipede" that combines ultrahigh density, terabit capacity, small form factor, and high data rate. Ultrahigh storage density has been demonstrated by a new thermomechanical local-probe technique to store, read back, and erase data in very thin polymer films. With this new technique, nanometer-sized bit indentations and pitch sizes have been made by a single cantilever/tip into thin polymer layers, resulting in a data storage densities of up to 1 Tb/in 2 . High data rates are achieved by parallel operation of large two-dimensional (2-D) atomic force microscope (AFM) arrays that have been batch-fabricated by silicon surface-micromachining techniques. The very large-scale integration (VLSI) of micro/nanomechanical devices (cantilevers/tips) on a single chip leads to the largest and densest 2-D array of 32 32 (1024) AFM cantilevers with integrated write/read/erase storage functionality ever built. Time-multiplexed electronics control the functional storage cycles for parallel operation of the millipede array chip. Initial areal densities of 100-200 Gb/in 2 have been achieved with the 32 32 array chip, which has potential for further improvements. A complete prototype system demonstrating the basic millipede functions has been built, and an integrated five-axis scanner device used in this prototype is described in detail. For millipede storage applications the polymer medium plays a crucial role. Based on a systematic study of different polymers with varying glass-transition temperatures, the underlying physical mechanism of bit writing has been identified, allowing the correlation of polymer properties with millipede-relevant parameters. In addition, a novel erase mechanism has been established that exploits the metastable nature of written bits.Index Terms-Atomic force microscope (AFM) array chips, microscanner, millipede, nano-indentation, polymer films, scanning probe data storage, thermomechanical write/read/erase.