摘要:
Radio-frequency (RF) excitation is used for direct detection of hybridization events at microelectrodes with surface-attached DNA oligomers. A homodyne reflectometer operates on a high frequency carrier to detect the presence of a low-frequency modulation signal. Without non-linearities in an interface, the modulation signal is not impressed upon the carrier signal. As such, the reflectometer can sensitively measure changes in dielectric properties without interference from other sources of capacitance/resistance unrelated to the reaction at the surface.
摘要:
An improved antenna for microwave ablation uses a triaxial design which reduces reflected energy allowing higher power ablation and/or a smaller diameter feeder line to the antenna.
摘要:
The present invention relates to systems and devices for delivering energy to tissue for a wide variety of applications, including medical procedures (e.g., tissue ablation, resection, cautery, vascular thrombosis, treatment of cardiac arrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). In particular, the present invention relates to systems and devices for the delivery of energy employing a center fed dipole component. In certain embodiments, methods are provided for treating a tissue region (e.g., a tumor) through application of energy with the systems and devices of the present invention.
摘要:
A method disclosed for producing polymer-based cantilevers for use in atomic force microscopy in a batch process. The method includes forming a mold in a mold material, for example PDMS, using a master cantilever, removing the master cantilever from the mold material to reveal a mold cavity, filling the mold cavity with plastic, for example polystyrene, to form a plastic cantilever in the mold, and removing the plastic cantilever from the mold, for example using adhesive tape or flexing the mold. At least one surface of the plastic cantilever can be coated with a reflective metal, such as gold. The plastic cantilever can be functionalized for use in magnetic force microscopy by attaching a probe tip formed of magnetic metal, for example a 10 μm nickel sphere.
摘要:
An improved antenna for microwave ablation uses a triaxial design which reduces reflected energy allowing higher power ablation and/or a smaller diameter feeder line to the antenna.
摘要:
A left-handed nonlinear transmission line system has multiple nonlinear capacitors connected in series between input and output terminals and multiple inductances connected in parallel between the nonlinear capacitors and a return conductor extending between the input and output terminals. The nonlinear capacitors have a capacitance characteristic that changes with the voltage applied across the capacitors, such as a capacitance that decreases with increasing voltage. A radio frequency signal source is coupled to the input terminals and provides power at a selected drive frequency. Depending on the frequency of the drive signal with respect to the Bragg cutoff frequency of the nonlinear transmission line, the output signal may include a strong signal component at the third harmonic of the input drive signal frequency, components at higher harmonics, or components at fractional frequencies of the input drive signal frequency. Parametric generation of other signal waves that are phase matched with the signal wave produced by the input drive signal is also possible under appropriate conditions. The left-handed nonlinear transmission line system generates such output signal frequencies with high efficiency.
摘要:
The present invention relates to radio-frequency identification (RFID) tags that produce a unique radar signature by passive reflection of an electromagnetic signal. In particular, provided herein are frequency-, phase-, and/or amplitude-shift encoded RFID tags, and methods of use and manufacture thereof.
摘要:
Dielectric spectroscopy is carried out by coupling non-radiated microwave energy from an antenna to a sample to detect changes in the permittivity of the sample within the antenna's near field. The frequency response of the antenna exhibits resonant frequencies in a frequency range of interest. Changes in the sample as a result of changes in environmental conditions of the sample are exhibited as changes in the antenna's resonant frequency or frequencies. The changes in the positions of the peaks with changes in environmental conditions can be correlated to changes in the condition of the sample, such as unfolding of proteins with increases in temperature of the sample.
摘要:
Semiconductor dot devices include a multiple layer semiconductor structure having a substrate, a back gate electrode layer, a quantum well layer, a tunnel barrier layer between the quantum well layer and the back gate, and a barrier layer above the quantum well layer. Multiple electrode gates are formed on the multi-layer semiconductor with the gates spaced from each other by a region beneath which quantum dots may be defined. Appropriate voltages applied to the electrodes allow the development and appropriate positioning of the quantum dots, allowing a large number of quantum dots be formed in a series with appropriate coupling between the dots.
摘要:
A method of fabricating high aspect ratio micromechanical tips is provided. The method includes, but is not limited to, forming an etchant protective island on a surface of a silicon substrate with the silicon substrate exposed around the island; isotropically etching the silicon substrate by reactive ion etching around the protective island to partially undercut the silicon substrate beneath the protective island; anisotropically etching, by deep reactive ion etching, the silicon surrounding the island to a desired depth to define a tip shaft of the desired height supported at a base by the substrate; removing the protective island from the tip; and sharpening the top of the tip shaft to an apex. Using the method, micromechanical tips having heights greater than at least 30 μm have been obtained while maintaining the vertical sidewall necessary for both AFM and scanning near-field microwave microscopy (SNMM) profiling applications.