Simultaneous transmission and reception on all elements of an array: binary code excitation

Pulse-echo arrays are used in radar, sonar, seismic, medical and non-destructive evaluation. There is a trend to produce arrays with an ever-increasing number of elements. This trend presents two major challenges: (i) often the size of the elements is reduced resulting in a lower signal-to-noise ratio (SNR) and (ii) the time required to record all of the signals that correspond to every transmit–receive path increases. Coded sequences with good autocorrelation properties can increase the SNR while orthogonal sets can be used to simultaneously acquire all of the signals that correspond to every transmit–receive path. However, a central problem of conventional coded sequences is that they cannot achieve good autocorrelation and orthogonality properties simultaneously due to their length being limited by the location of the closest reflectors. In this paper, a solution to this problem is presented by using coded sequences that have receive intervals. The proposed approach can be more than one order of magnitude faster than conventional methods. In addition, binary excitation and quantization can be employed, which reduces the data throughput by roughly an order of magnitude and allows for higher sampling rates. While this concept is generally applicable to any field, a 16-element system was built to experimentally demonstrate this principle for the first time using a conventional medical ultrasound probe.

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Application of Novel Low Current OBIRCH Amplifier and Nanoprobing to Identify Subtle Leakages in Advanced Node Technologies

10.31399/asm.cp.istfa2018p0303 ◽

2018 ◽

Author(s):

Satish Kodali ◽

Liangshan Chen ◽

Yuting Wei ◽

Tanya Schaeffer ◽

Chong Khiam Oh

Keyword(s):

Signal To Noise Ratio ◽

Semiconductor Industry ◽

Fault Isolation ◽

Ring Oscillator ◽

High Signal ◽

The Novel ◽

Resistance Change ◽

Three Samples ◽

Relative Threshold ◽

First Time

Abstract Optical beam induced resistance change (OBIRCH) is a very well-adapted technique for static fault isolation in the semiconductor industry. Novel low current OBIRCH amplifier is used to facilitate safe test condition requirements for advanced nodes. This paper shows the differences between the earlier and novel generation OBIRCH amplifiers. Ring oscillator high standby leakage samples are analyzed using the novel generation amplifier. High signal to noise ratio at applied low bias and current levels on device under test are shown on various samples. Further, a metric to demonstrate the SNR to device performance is also discussed. OBIRCH analysis is performed on all the three samples for nanoprobing of, and physical characterization on, the leakage. The resulting spots were calibrated and classified. It is noted that the calibration metric can be successfully used for the first time to estimate the relative threshold voltage of individual transistors in advanced process nodes.

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Detection and Quantification of 7-Hydroxydehydroepiandrosterone Epimers in Three Body Fluids

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20020010 ◽

2002 ◽

Vol 67 (1) ◽

pp. 10-18 ◽

Cited By ~ 1

Author(s):

Richard Hampl ◽

Martin Hill ◽

Luboslav Stárka

Keyword(s):

Healthy Subjects ◽

Serum Levels ◽

Body Fluids ◽

Gas Chromatography Mass Spectrometry ◽

Specific Radioimmunoassay ◽

Order Of Magnitude ◽

Three Body ◽

First Time ◽

Nanomolar Range ◽

Detection And Quantification

3β,7α-Dihydroxyandrost-5-en-17-one (1) (7α-OH-DHEA) and its 7β-hydroxy epimer 2 (7β-OH-DHEA) - 7α- and 7β-hydroxydehydroepiandrosterone - were detected and quantified in three human body fluids: in blood serum, saliva and ejaculate. Specific radioimmunoassay and gas chromatography-mass spectrometry have been used. For the first time the data on changes of these dehydroepiandrosterone metabolites are reported for a representative group of healthy subjects of both sexes (172 females and 217 males) during the life span. The serum levels of both 7-hydroxydehydroepiandrosterone epimers in serum and also in semen were in the low nanomolar range, while concentrations by one order of magnitude lower were found in saliva, but still within the detection limit. The results will serve as a basis for comparative studies of 7-hydroxydehydroepiandrosterone levels under various pathophysiological conditions, with a particular respect to autoimmune disorders.

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Counterfactual ghost imaging

npj Quantum Information ◽

10.1038/s41534-021-00411-4 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jonte R. Hance ◽

John Rarity

Keyword(s):

Signal To Noise Ratio ◽

Ghost Imaging ◽

Signal To Noise ◽

Interesting Phenomenon ◽

Order Of Magnitude ◽

Noise Ratio

AbstractWe give a protocol for ghost imaging in a way that is always counterfactual—while imaging an object, no light interacts with that object. This extends the idea of counterfactuality beyond communication, showing how this interesting phenomenon can be leveraged for metrology. Given, in the infinite limit, no photons ever go to the imaged object, it presents a method of imaging even the most light-sensitive of objects without damaging them. Even when not in the infinite limit, it still provides a many-fold improvement in visibility and signal-to-noise ratio over previous protocols, with over an order of magnitude reduction in absorbed intensity.

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Frequency-diverse multimode millimetre-wave constant-ϵr lens-loaded cavity

Scientific Reports ◽

10.1038/s41598-020-78964-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

M. A. B. Abbasi ◽

V. F. Fusco ◽

O. Yurduseven ◽

T. Fromenteze

Keyword(s):

Signal To Noise Ratio ◽

Cost Effective ◽

Doa Estimation ◽

Frequency Diversity ◽

Millimetre Wave ◽

Single Lens ◽

Dielectric Lens ◽

Diversity Principle ◽

First Time ◽

Multi Mode

AbstractThis paper presents a physical frequency-diverse multimode lens-loaded cavity, designed and used for the purpose of the direction of arrival (DoA) estimation in millimetre-wave frequency bands for 5G and beyond. The multi-mode mechanism is realized using an electrically-large cavity, generating spatio-temporally incoherent radiation masks leveraging the frequency-diversity principle. It has been shown for the first time that by placing a spherical constant dielectric lens (constant-ϵr) in front of the radiating aperture of the cavity, the spatial incoherence of the radiation modes can be enhanced. The lens-loaded cavity requires only a single lens and output port, making the hardware development much simpler and cost-effective compared to conventional DoA estimators where multiple antennas and receivers are classically required. Using the lens-loaded architecture, an increase of up to 6 dB is achieved in the peak gain of the synthesized quasi-random sampling bases from the frequency-diverse cavity. Despite the fact that the practical frequency-diverse cavity uses a limited subset of quasi-orthogonal modes below the upper bound limit of the number of theoretical modes, it is shown that the proposed lens-loaded cavity is capable of accurate DoA estimation. This is achieved thanks to the sufficient orthogonality of the leveraged modes and to the presence of the spherical constant-ϵr lens which increases the signal-to-noise ratio (SNR) of the received signal. Experimental results are shown to verify the proposed approach.

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Statistical Uncertainty of DNS in Geometries without Homogeneous Directions

Applied Sciences ◽

10.3390/app11041399 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1399

Author(s):

Jure Oder ◽

Cédric Flageul ◽

Iztok Tiselj

Keyword(s):

Channel Flow ◽

A Priori ◽

Time Integration ◽

Navier Stokes ◽

Statistical Uncertainty ◽

Time Step ◽

Order Of Magnitude ◽

Averaging Time ◽

The Individual ◽

Time Required

In this paper, we present uncertainties of statistical quantities of direct numerical simulations (DNS) with small numerical errors. The uncertainties are analysed for channel flow and a flow separation case in a confined backward facing step (BFS) geometry. The infinite channel flow case has two homogeneous directions and this is usually exploited to speed-up the convergence of the results. As we show, such a procedure reduces statistical uncertainties of the results by up to an order of magnitude. This effect is strongest in the near wall regions. In the case of flow over a confined BFS, there are no such directions and thus very long integration times are required. The individual statistical quantities converge with the square root of time integration so, in order to improve the uncertainty by a factor of two, the simulation has to be prolonged by a factor of four. We provide an estimator that can be used to evaluate a priori the DNS relative statistical uncertainties from results obtained with a Reynolds Averaged Navier Stokes simulation. In the DNS, the estimator can be used to predict the averaging time and with it the simulation time required to achieve a certain relative statistical uncertainty of results. For accurate evaluation of averages and their uncertainties, it is not required to use every time step of the DNS. We observe that statistical uncertainty of the results is uninfluenced by reducing the number of samples to the point where the period between two consecutive samples measured in Courant–Friedrichss–Levy (CFL) condition units is below one. Nevertheless, crossing this limit, the estimates of uncertainties start to exhibit significant growth.

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Identification of pigments in artworks by inverse tangent derivative of spectrum and a new filtering method

Heritage Science ◽

10.1186/s40494-020-00438-4 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

F. Fazlali ◽

S. Gorji Kandi

Keyword(s):

Reflectance Spectrum ◽

Practical Method ◽

Chemical Methods ◽

Munk Function ◽

Absorption Of Light ◽

Spectrophotometric Data ◽

First Time ◽

Non Destructive ◽

Derivatives Of

Abstract Employing an economical and non-destructive method for identifying pigments utilized in artworks is a significant aspect for preserving their antiquity value. One of the non-destructive methods for this purpose is spectrophotometry, which is based on the selected absorption of light. Mathematical descriptive methods such as derivatives of the reflectance spectrum, the Kubelka–Munk function and logarithm have been employed for the characterization of the peak features corresponding to the spectrophotometric data. In the present study, the mentioned mathematical descriptive methods were investigated with the aim to characterize the constituents of an Iranian artwork but were not efficient for the samples. Therefore, inverse tangent derivative equation was developed on spectral data for the first time, providing considerable details in the profile of reflectance curves. In the next part, to have a simpler and more practical method it was suggested to use filters made up of pure pigments. By using these filters and placing them on the samples, imaging was done. Then, images of samples with and without filter were evaluated and pure pigments were distinguished. The mentioned methods were also used to identify pigments in a modern Iranian painting specimen. The results confirmed these methods with reliable answers indicating that physical methods (alongside chemical methods) can also be effective in determining the types of pigments.

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Analyzing of Coatings on Steel - Reinforced Concrete Elements by Mobile NMR

Archives of Civil Engineering ◽

10.1515/ace-2015-0052 ◽

2016 ◽

Vol 62 (1) ◽

pp. 65-82 ◽

Cited By ~ 2

Author(s):

J. Orlowsky

Keyword(s):

Reinforced Concrete ◽

Potential Effect ◽

Building Site ◽

Steel Reinforced Concrete ◽

Mobile Nmr ◽

The Individual ◽

First Time ◽

Concrete Elements ◽

Non Destructive

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

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Ultra-Low Resistance Ni-Based Contacts to n-InP: the Dependence of Contact Resistivity on the Condition of the Metal-Semiconductor Interface

MRS Proceedings ◽

10.1557/proc-318-171 ◽

1993 ◽

Vol 318 ◽

Cited By ~ 1

Author(s):

Navid S. Fatemi ◽

Victor G. Weizer

Keyword(s):

Deposition Process ◽

Atomic Ratio ◽

Contact Resistivity ◽

Semiconductor Interface ◽

Near Surface ◽

Process Use ◽

Fold Reduction ◽

Specific Contact ◽

Order Of Magnitude ◽

First Time

ABSTRACTNear-theoretical-minimum values of specific contact resistivity, ρc (in the mid-to-low E-8 Ω-cm2 range) have been achieved for Ni-based contacts to moderately doped (2E18 cm−3) n-type InP. In each case these values are an order of magnitude lower than those previously achieved. These ultra-low resistivities are shown to result when the metallurgical interaction rate between the contact metal and the semiconductor is sufficiently reduced. Several methods of reducing the metal-InP reaction rate and thus achieving lowered resistivity values are demonstrated. We show, for instance, that the introduction of a thin (100Å) Au layer at the metal-InP interface retards metal-semiconductor intermixing during sintering and results in a ten-fold reduction in pc. Another method consists of ensuring the perfection of the near-surface InP lattice prior to and during contact deposition process. Use of this technique has enabled us to fabricate, for the first time, Ni-only contacts with pc values in the low E-8 Ω-cm2 range. We present an explanation for these observations that is based upon the magnitude of the In-to-P atomic ratio at the metal-InP interface.

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Rapid Polymer/Gas Solution Formation for Continuous Production of Microcellular Plastics

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2831079 ◽

1996 ◽

Vol 118 (4) ◽

pp. 639-645 ◽

Cited By ~ 53

Author(s):

C. B. Park ◽

N. P. Suh

Keyword(s):

Rapid Heating ◽

Continuous Production ◽

Batch Process ◽

Bubble Nucleation ◽

Cycle Times ◽

Solution Formation ◽

Microcellular Plastics ◽

Diffusion Phenomena ◽

Order Of Magnitude ◽

Time Required

An extrusion system that can create a polymer/gas solution rapidly for continuous processing of microcellular plastics is presented. Microcellular plastics are characterized by cell densities greater than 109 cells/cm3 and fully grown cells smaller than 10 μm. Previously these microcellular structures have been produced in a batch process by saturating a polymeric material with an inert gas under high pressure followed by inducing a rapid drop in the gas solubility. The diffusion phenomena encountered in this batch processing is typically slow, resulting in long cycle times. In order to produce microcellular plastics at industrial production rates, a means for the rapid solution formation is developed. The processing time required for completing the solution formation in the system was estimated from experimental data and the dispersive mixing theory based on an order-of-magnitude analysis. A means for promoting high bubble nucleation rates in the gas-saturated polymer via rapid heating is also discussed. The feasibility of the continuous production of microcellular plastics by the rapid polymer/gas solution formation and rapid heating was demonstrated through experiments. The paper includes not only a brief treatment of the basic science of the polymer/gas systems, but also the development of an industrially viable technology that fully utilizes the unique properties of microcellular plastics.

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