Within Saint Louis University’s (SLU) Department of Physics, research has been ongoing in the development of novel techniques for synthesis, characterization and measurement of low dimensional (1D and 2D) systems. This is in hopes to better understand how size, geometry or interfacing various materials and nanostructures influences the properties of the resulting systems.

Nanolithography Research
Nanolithography in general terms is concerned with the study and application of fabricating nanometer-scale structures, meaning patterns with at least one lateral dimension between 1 and 100 nm. A prime focus is very largescale integration (VLSI) and ultralarge-scale integration (ULSI) technology of nanoelectromechanical (NEMS) systems, and the need for better atomic-scale understanding of issues arising from the miniaturization of silicon devices. Under the direction of Dr. Irma Kuljanishvili, who heads up SLUs nanomaterials and nanofabrication research lab, the groups focus is on This approach is similar to a technique known as dip pen nanolithography.

In this technique, AFM tips or sharp needles can be employed to transfer small, femtoliter volumes of molecular solutions, or other liquid-based ink, to predefined locations on the surface of samples.

Carbon nanotubes, grapheme and other atomically monolayered materials are being considered as prime candidates for nanoscale science and technology applications, due to their unique and superior combination of electrical, thermal, optical and mechanical properties, says Kuljanishvili.

SLU's Negative-Stiffness Vibration Isolation System

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Featured Product: SM-1 Large Capacity, Low Frequency Vibration Isolators

• Vertical natural frequency of 1/2 Hz or less can be achieved over the entire load range.
  
• Horizontal natural frequency is load dependent. 1/2 Hz or less can be achieved at or near the nominal load.
  
• See typical transmissibility curve Performance for the SM-1.

Minus K's SM-1 is low frequency vibration isolator for weight loads from 500 to 4200 lbs. and 1/2 Hz performance vertical and horizontal.

The SM-1 negative-stiffness isolator is the basic building block of the FP-1 Floor Platform and other heavy multiple isolator systems. They require no air or electricity.

This isolator has the same basic features of our all passive, negative-stiffness, manually-adjustable bench top isolators. It offers our very-low frequency isolation performance for payloads of many thousands of pounds.

SM-1 isolator can be used alone or with any number of additional units to achieve higher capacity systems. They can be arranged in many geometrical configurations to suit your application.

The SM-1 isolators can also be placed on pedestals to increase the height of the isolation system.

Pricing & Specifications

Notice that between points A and B, displacement is increasing while force is decreasing. Thus, the structure’s stiffness is negative in that region.

Negative-stiffness vibration isolators consist of a horizontal isolator and a vertical isolator connected in series. To counter motions that involve rotation (pitch and roll), a tilt motion pad can also be connected in series with the horizontal and vertical isolators.

The horizontal isolator consists of two fixed-free vertical beams (columns) supporting a weight. The weight imparts both eccentric (off-axis) axial compressive load and a transverse bending load. This phenomenon is referred to as the beam-column effect and causes the lateral bending stiffness of the beams to decrease. In effect, the isolator is acting as a horizontal spring with a negative-stiffness mechanism.

The horizontal isolator is designed to take advantage of the beam-column effect, allowing it to act like a negative-stiffness mechanism.

Vertical motion is addressed using two horizontal flexures loaded in compression, which form a negative-stiffness mechanism. The flexures are supported at their outer ends and connected to a stiff spring at their inner ends. The stiffness of the isolator is determined by the design of the flexures and by their compressive load.

Two flexures, fixed at their outer ends and connected to a spring at their inner ends, form a negative-stiffness mechanism that isolates equipment from vertical motion due to vibrations.

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Close-up of a stylus and LP record vinyl grooves

"Vinyl remains unsurpassed for reproducing music,” said Mark Döhmann, Founder of Döhmann Audio. To convey vinyls rich, nuanced potential a turntable must have precise speed control and operate without producing mechanical or electronic noise. The goal is an uncompromised signal emerging from a silent background, resulting from precisely designed construction that eliminates noise and gives precision speed control for ideal playback.

This goal has been very closely approximated with the release of the Helix One and Helix Two turntables, representing a breakthrough in analog playback design and execution. These turntables are a showcase for micro-signal architecture, a new way of thinking borne from the world of ultra-precision sub-atomic research, where the removal of unwanted vibration is critical to achieving precision results.

The Helix One and Helix Two turntables reward the listener with the closest facsimile to master tape yet realized. Their specifications demand the ultimate in noise suppression and vibration isolation systems, allowing the turntables and pick-up arms to deliver the micro-signals buried in the vinyl grooves of LPs.

Every aspect of the turntables' design requires the preservation of the micro-signals found in the grooves of the LP to be retrieved with as little modification and distortion as physically and electronically possible, added Döhmann. The turntables incorporate a number of engineering advances to deliver the lowest resonance profile for any pickup arm and LP combination.

These engineering advances include: a) mechanical crossover technology; b) a tri-modal platter system; c) an edge-damping ring; d) a tone arm damping system; e) resonance-tuned suspension; f) a diamond-like coating, amorphous material-bearing friction modifier; g) high-torque, adjustable-drive speed selections; and h) a velocity adjustment lock.

But what contributes to making the Helix One and Helix Two turntables truly unique is their highly precise, fully-integrated vibration isolation system.

The Need For Vibration Isolation
Vibration isolation in the playback process of high-end audio systems is crucial. Any external vibration, no matter how slight, even someone walking near the turntable or vibration from floor-mounted speakers, is sensed by the turntables stylus and affects the sound being played back from the record. Capacitors, resistors, transistors, tube amplifiers and other electronic components are likewise sensitive to vibration.

Analog audio is a very detailed and information rich storage and retrieval mechanism, continued Döhmann. The enemy of retrieval information is vibration, which can modulate with the needle as it works its way through the groove. If you can remove exterior vibration and allow the needle to operate in an optimally quiet method or platform, then you will get more information out because your noise is much lower.

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More at our Audio & Turntable Vibration Isolation Applications page...

(2016 Legacy Article) The tunable microwave-frequency alternating current scanning tunneling microscope (ACSTM) has opened the possibility of recording local spectra and local chemical information on insulator surfaces, much like the conventional scanning tunneling microscope (STM) has done for metals and semiconductors..

Spectroscopy in the microwave frequency range enables unrealizable measurements on conducting substrates, such as the rotational spectroscopy of a single adsorbed molecule. Developed in the early 1990s by Professor Paul Weiss, the nano-pioneering Director of the Weiss Group, a nanotechnology research unit of UCLAs California NanoSystems Institute, the ACSTMs single-molecule measurement techniques have illuminated unprecedented details of chemical behavior, including observations of the motion of a single molecule on a surface, and even the vibration of a single bond within a molecule. Such measurements are critical to understanding entities ranging from single atoms to the most complex protein assemblies.We use molecular design, tailored syntheses, intermolecular interactions and selective chemistry to direct molecules into desired positions to create nanostructures, to connect functional molecules to the outside world, and to serve as test structures for measuring single or bundled molecules, said David McMillan, Lead Technician at the Weiss Group.

Critical to understanding these variations has been developing the means to make tens- to hundreds-of-thousands of independent single-molecule measurements in order to develop sufficiently significant statistical distributions, while retaining the heterogeneity inherent in the measurements.

Vibration isolation
To achieve these nano-level chemical and spectroscopic data sets, the ACSTM must be positioned in an ultra-stable operating environment, one free of low-frequency vibrations.The lab was using almost exclusively optical tables on pneumatic isolation, said McMillan.One of our big problems has been space constraint. We needed smaller pneumatic optical tables to fit. But as the air tables get smaller, their vibration isolation performance diminishes.

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The compound microscope has evolved from an instrument providing simple contrast viewing, into super-resolution systems capable of sub-diffraction accuracy. Its two platforms, upright and inverted, can be found in most laboratories doing cellular research, such as in biotech and pharmaceutical. Upright microscopes are used for viewing glass slides, and inverted for viewing live cells in Petri dishes. Despite its imaging advances, the basic architecture of the compound microscope has not substantially been modified in centuries.

This has now changed, with the recent release of the Revolve hybrid compound microscope, developed by Echo Laboratories (Echo), which has set a new precedent in microscope usability and design. The Revolve combines the full functionality of both upright and inverted microscopes in one instrument, and can switch between the two imaging modes relatively swiftly and easily. This gives the flexibility to view many types of samples with one microscope to a level of 300 350 nanometers resolution.

“More than 70 percent of labs end up having both inverted and upright microscopes,” said Jeff Huber, Director of Sales for Echo Laboratories. “But both uprights and inverts use similar objectives, illuminators, position systems and cameras. Why duplicate all of these expensive components? And why take up valuable lab space with two instruments? So, Echo Laboratories engineered a way to merge these two systems into one unified instrument, which is the Revolve microscope.”

Brightfield, Phase Contrast and Epifluorescence Imaging with iPad and Wireless Upload
his is a compound, infinity-path microscope, with applications for brightfield, phase contrast, and epi-fluorescence imaging. Current glass selection includes the entire line of Olympus objectives. Due to the unique nature of the upright/inverted combination, both a high-NA and long-working-distance transmitted-light condensers are available to support phase and brightfield. A high-accuracy locking mechanism is used to securely hold the condenser assembly in place, while still allowing for easy removal by a single lever.

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