This work was supported by the National Natural Science Foundation of China (NSFC) (Grant 62075238, 61675231) and&#160;the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB24030600).

1. Optical coupling
<ol>
	<li>Polish the end-face of the MRR on a grinding plate using 1.5 &#956;m abrasive powders (aluminum oxide) mixed with water for 5 min.</li>
	<li>Fix the MRR with a chip fixture and place an eight-channel FA on a six-axis coupling stage, which includes three linear stages with a resolution of 50 nm and three angle stages with a resolution of 0.003&#176;. The patches of the MRR and FA are 250 &#956;m.</li>
	<li>Use a 1,550 nm laser as an optical source for real-time monitoring of the coupling ef...

<ol>
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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+broadband+chip-scale+optical+frequency+synthesizer+at+2.7x10-16+relative+uncertainty.">A broadband chip-scale optical frequency synthesizer at 2.7x10-16 relative uncertainty.</a> Science Advance. 2, 1501489 (2016).</li><li>Liang, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+spectral+purity+Kerr+frequency+comb+radio+frequency+photonic+oscillator.">High spectral purity Kerr frequency comb radio frequency photonic oscillator.</a> Nature Communications. 6, 7957 (2015).</li><li>Liao, P. 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On-chip DKSs provide novel compact coherent optical sources and exhibit excellent application prospects in optical metrology, molecular spectroscopy, and other functions. For commercial applications, compact packaged micro-comb sources are essential. This protocol provides a practical approach to make a packaged micro-comb that benefits from the reliable, low coupling loss connection between the MRR and FA, as well as a robust thermal-controlled DKS generation method. Therefore, our experiments are no longer coupling sta...

The steady DKSs in microresonators, where the cavity dispersion is balanced by Kerr nonlinearity, as well as the Kerr gain and cavity dissipation1, have attracted great interest in the scientific research community for their ultra-high repetition rate, compact size, and low cost2. In the time domain, DKSs are stable pulse trains that have been used for high-speed ranging measurement3 and molecular spectroscopy4. In the frequency domain, DKSs have a series of frequency lines with equal frequency spacing that are suitable for wavelength-division-multiplex (WDM) communications systems5,6, optical frequency synthesis7,8, and ultra-low noise microwave generation9,10, etc. The phase noise or linewidth of comb lines directly affects the performance of these application systems. It has been proven that all the comb lines have a similar linewidth with the pump11. Therefore, using an ultra-narrow linewidth laser as a pump is an effective approach to improve the performance of DKSs. However, the pumps of most reported DKSs are frequency sweeping external cavity diode lasers (ECDLs), which suffer from relatively high noise and have a broad linewidth on the order of tens to hundreds of kHz. Compared with tunable lasers, fixed-frequency lasers have less noise, narrower linewidths&#160;and smaller volume. For example, Menlo systems can provide ultra-stable laser products with a linewidth of less than 1 Hz. Using such a frequency fixed laser as a pump can significantly reduce the noise of the generated DKSs. Recently, microheater or thermoelectric cooler (TEC)-based thermal tuning methods have been used for DKSs generation12,13,14.
Repetition rate stability is another important parameter of DKSs. Generally, frequency counters are used to characterize the frequency stability of DKSs within a gate time, which is generally on the order of a microsecond to a thousand seconds15,16. Limited by the bandwidth of the photodetector and frequency counter, electro-optic modulators or reference lasers are typically used to lower the detected frequency when the free-spectral-range (FSR) of the DKSs is over 100 GHz. This not only increases the complexity of test systems, but also produces additional measurement errors caused by the stability of RF sources or reference lasers.
In this paper, a micro-ring resonator (MRR) is butterfly packaged with a commercial TEC chip that is used to control the operation temperature. Using a frequency fixed laser with a linewidth of 100 Hz as a pump, soliton crystals (SCs) are stably generated by manually decreasing the operating temperature; these are special DKSs that can completely fill a resonator with collectively ordered ensembles of copropagating solitons17. To the best of our knowledge, this is the narrowest linewidth pump in DKSs generation experiments. The power spectral density (PSD) spectrum of every comb line is measured based on a delayed self-heterodyne interferometer (DSHI) method. Benefitting from the ultra-narrow linewidth of the comb lines, the repetition rate instability of soliton crystals (SCs) is derived from the central frequency drift of the PSD curves. For the SC with a single vacancy, we obtained a repetition rate instability of ~53.24 Hz within 10 &#181;s and ~509.32 Hz within 125 &#181;s.
The protocol consists of several main stages: First, the MRR is coupled with a fiber array (FA) using a six-axis coupling stage. The MRR is fabricated by a high-index doped silica glass platform18,19. Then, the MRR is packaged into a 14-pin butterfly package, which increases the stability for the experiments. SCs are generated using a thermal-controlled method. Finally, the repetition rate fluctuations of SCs are measured by a DSHI method.

<table border="0" cellpadding="0" cellspacing="0" style="width:1421px;" width="1421">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:299px;">6-axis coupling stage</td>
			<td style="width:323px;">Suruga Seiki</td>
			<td style="width:161px;">KXC620G 
			KGW060</td>
			<td style="width:639px;">Contains 3 linear motorized translation states and 3 angular motorized rotational stages. 
			Linear state: Minimum stepping: 0.05 &#956;m; Travel: 20mm; Max.speed: 25mm/s; Repeatability: +/-0.3 &#956;m; Rotational stage:Travel: &#177;8&#176;; Resolution/pulse: 0.003 degree; Repeatability:&#177;0.005&#176;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Abrasive powder</td>
			<td style="width:323px;">Shenyang Kejing Auto-Instrument Co., LTD</td>
			<td>2980002</td>
			<td>Silicon carbide, granularity: 1.5 &#956;m</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">Glue 3410</td>
			<td style="width:323px;">Electronic Materials Incorporated</td>
			<td style="width:161px;">Optocast 3410</td>
			<td style="width:639px;">Optocast 3410 is an ultra violet light and heat curable epoxy suitable for opto-electronic assembly. It cures rapidly when exposed to U.V. light in the 320-380 nm.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">High-index doped silica glass</td>
			<td style="width:323px;">Home-made</td>
			<td style="width:161px;">-</td>
			<td style="width:639px;">The MRR is fabricated by a high index doped silica glass platform. The waveguide section is 2&#215;3 &#956;m and radius is 592.1 &#956;m, corresponding to FSR of 49 GHz.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Pump laser</td>
			<td style="width:323px;">NKT Photonics</td>
			<td style="width:161px;">E15</td>
			<td style="width:639px;">It is a continuous wave fiber laser with linewidth of 100 Hz.</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:299px;">Ultrastable Laser</td>
			<td style="width:323px;">Menlosystems</td>
			<td style="width:161px;">ORS</td>
			<td>State-of-the-art linewidth (&#60;1Hz) and stability (&#60;2 x 10-15 Hz)</td>
		</tr>
	</tbody>
</table>

rapid repetition rate fluctuation measurement of soliton crystals in a microresonator

Temporal solitons have attracted great interest in the past decades for their behavior in a steady state, where the dispersion is balanced by the nonlinearity in a propagation Kerr medium. The development of dissipative Kerr solitons (DKSs) in high-Q microcavities drives a novel, compact, chip-scale soliton source. When DKSs serve as femtosecond pulses, the repetition rate fluctuation can be applied to ultrahigh precision metrology, high-speed optical sampling, and optical clocks, etc. In this paper, the rapid repetition rate fluctuation of soliton crystals (SCs), a special state of DKSs where particle-like solitons are tightly packed and fully occupy a resonator, is measured based on the well-known delayed self-heterodyne method. The SCs are generated using a thermal-controlled method. The pump is a frequency fixed laser with a linewidth of 100 Hz. The integral time in frequency fluctuation measurements is controlled by the length of the delay fiber. For a SC with a single vacancy, the repetition rate fluctuations are ~53.24 Hz within 10 &#181;s and ~509.32 Hz within 125 &#181;s, respectively.

Figure 3 shows the transmission power trace while a resonance thermal was tuned across the pump. There was an obvious power step that indicated the generation of SCs. The step had similar power compared with its precursor, the modulational instability comb. Therefore, the generation of SCs was not tuning speed dependent. The SCs exhibited a great variety of states, including vacancies (Schottky defects), Frenkel defects, and superstructure12,<sup class="xre...

Watch this Scientific Journal Video about Rapid Repetition Rate Fluctuation Measurement of Soliton Crystals in a Microresonator at JoVE.com

Rapid Repetition Rate Fluctuation Measurement of Soliton Crystals in a Microresonator

Here, we present a protocol to generate soliton crystals in a butterfly-packaged micro-ring resonator using a thermal tuned method. Further, the repetition rate fluctuations of a soliton crystal with a single vacancy are measured using a delayed self-heterodyne method.

Temporal solitons have attracted great interest in the past decades for their behavior in a steady state, where the dispersion is balanced by the ...

Recent years, dissipative Kerr soliton has become a novel chip-scale coherent light source, which has attracted great attention for the enormous value in soliton physics research and practical applications. Dissipative Kerr soliton has high repetition rate. So it is a challenge to measure the relative parameters, especially the repetition rate fluctuation.In our work, we figure out a way to get it. Meanwhile, a robust package is necessary for practical applications. Our protocol provides an effective method for on-chip micro-ring resonator packaging, soliton generation, and measurement of repetition rate fluctuation.To begin, fix the micro-ring resonator with a chip fixture. On a six axis coupling stage, which includes three linear stages with a resolution of 50 nanometers and three angle stages with a resolution of 0.003 degrees, place an eight channel fiber array. Use a 1, 550 nanometer laser as an optical source for real-time monitoring of the coupling efficiency.Carefully adjust the position of the fiber array. Measure the input power and output power by an optical power meter. Keep the inset loss at the minimum value, typically less than six decibels, corresponding to a coupling loss of less than three decibels per facet.Use an ultraviolet curved adhesive to glue the micro-ring resonator and fiber array. Place the adhesive on the side edge of the contacting surface to ensure that there is no glue on the optical path. Expose the UV curved adhesive to a UV lamp for 150 seconds and bake in a chamber at 120 degrees Celsius for more than one hour.Co agglutinate a 10.2 millimeter by 6.05 millimeter thermal electric cooler chip with a maximum power of 3.9 Watts to the base plate of a standard 14 pin butterfly package using silver glue. Sauter the two electrodes of the thermoelectric cooler chip to two pins of the butterfly package. Paste a tungsten plate to the surface of the thermal electric cooler chip using silver glue.Use the tungsten plate as a heat sink to fill the gap between the thermal electric cooler and the micro-ring resonator. Use an erbium doped fiber amplifier to boost the pump for micro comb generation. Control the polarization state of the pump using a fiber polarization controller.Connect all the devices using single mode fibers. Fix the wavelength of the pump laser. At 1556.3 nanometers, manually tune the operation temperature through an external commercial thermoelectric cooler controller to above 66 degrees Celsius, which is high enough to move a resonance of the micro-ring resonator to the top of the tungsten plate using silver glue, and fix the pigtail of the fiber array to the output board of the butterfly package to the red side of the pump.Monitor the output optical spectrum with an optical spectrum analyzer. Detect the output power trace with a three gigahertz photo detector and record with an oscilloscope. Set the output of the erbium doped fiber amplifier to 34 decibel milliwatts, or responding to an on-chip power of 30.5 decibel milliwatts, which ensures that there is enough power coupled into the micro-ring resonator for micro comb generation.Set the thermistor to two kilohms corresponding to an operating temperature of 66 degrees Celsius, then slowly decrease the operating temperature by increasing the set value of the thermistor. Tune the polarization of the pump by the fiber polarization controller, until a soliton crystal's step is observed at the falling edge of the triangular transmission power trace. When a palm like optical spectrum is observed on the optical spectrum analyzer, stop decreasing the operation temperature.The value of the thermistor was around at 5.6 kilohms in these experiments. Connect the generated soliton crystals to a tuneable band pass filter to extract an individual comb line. Set the pass band of the tuneable band pass filter to 0.1 nanometers.Tune its central wavelength over the full C and L band, and set the filter slope to 400 decibels per nanometer. Couple of the selected comb line to an asymmetric mock Zehnder interferometer. Use an acousto-optic modulator to shift the optical frequency in one arm of the asymmetric mock sender interferometer by 200 megahertz.The optical field in the other arm is delayed by a segment of optical fibers of two kilometers and 25 kilometers. Attach a photodiode to detect the output optical signal and use an electrical spectrum analyzer to analyze the power spectral density spectrum. Tune the central wavelength of the tuneable band pass filter.Measure the power spectral densities of every comb line. Using same method, measure the power spectral density curves of soliton crystals with a vacancy. Record the three decibel bandwidth of the power spectral density curve, and that'll enter your fit to it piecewise through a Python program.This figure shows the transmission powertrains while a resonance thermal was tuned across the pump. There was an obvious power step that indicated the generation of soliton crystals. A perfect soliton crystal with 27 solitons is shown here, as well as a soliton crystal with a single vacancy.The perfect soliton crystals based on a two kilometer and a 25 kilometer delay fiber were observed with power spectral density curves having flat tops, which were caused by the frequency fluctuation within the delay time. The typical optical spectrum of soliton crystals based on a two kilometer and a 25 kilometer delay fiber were fitted piecewise with linear lines plotted in blue. In summary, an on-chip micro-ring resonator is packed in a butterfly cell and a thermal tuning method is proposed generate soliton crystal.Finally, we use delayed self-heterodyne method to achieve the measurement of the repetition rate fluctuation.

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2.9K ビュー.  Chinese Academy of Sciences (CAS). 近年、散逸性カーソリトンは、ソリトン物理学研究や実用化において大きな価値を高めている、新しいチップスケールのコヒーレント光源となっています。散逸カーソリトンは、高い繰り返し率を有する。したがって、相対パラメータ、特に繰り返しレートの変動を測定することは困難です。私たちの仕事では、それを得る方法を見つけ出します。一方、実用的な?...

ビデオ: Rapid Repetition Rate Fluctuation Measurement of Soliton Crystals in a Microresonator

Here, we present a protocol to generate soliton crystals in a butterfly-packaged micro-ring resonator using a thermal tuned method. Further, the repetition rate fluctuations of a soliton crystal with a single vacancy are measured using a delayed self-heterodyne...

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Here we describe a method for rapid and accurate measurement of flight performance in Drosophila, enabling high-throughput...

An Improved Method for Accurate and Rapid Measurement of Flight Performance in Drosophila

erythrocyte sedimentation rate: a physics-driven characterization in a medical context

Erythrocyte Sedimentation Rate: A Physics-Driven Characterization in a Medical Context

Erythrocyte sedimentation rate (ESR) is a physical parameter, often used in routine health checks and medical diagnosis. A theoretical model that allows to extract physically-meaningful parameters from the whole sedimentation curve, based on modern colloidal knowledge, has recently been developed. Here, we present a protocol to automatically collect the ESR over time, and extract the parameters of this recent model from this automated data collection. These refined parameters are also likely to...

optimizing the growth of endothiapepsin crystals for serial crystallography experiments

Optimizing the Growth of Endothiapepsin Crystals for Serial Crystallography Experiments

The aim of this article is to give the viewer a solid understanding of how to transform their small-volume, vapor-diffusion protocol, for growing large, single protein crystals, into a large-volume batch micro-crystallization method for serial...

physiology lab demonstration: glomerular filtration rate in a rat

Physiology Lab Demonstration: Glomerular Filtration Rate in a Rat

The purpose of this protocol is to demonstrate the principles and techniques for measuring and calculating glomerular filtration rate, urine flow rate, and excretion of sodium and potassium in a rat. This demonstration can be used to provide students with an overall conceptual understanding of how to measure renal function.

Ultrasound Velocity Measurement in a Liquid Metal Electrode

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within &#177;2 &#176;C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries.

Ultrasound velocimetry is used to study mixing by fluid flow in liquid metal electrodes. The focus of this manuscript is to illustrate the methods used for making precise, spatially-resolved ultrasound measurements while limiting oxidation and controlling and monitoring temperature, applied current, and the heater power being supplied.

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Silicon photonic chips have the potential to realize complex integrated quantum information processing circuits, including photon sources, qubit manipulation, and integrated single-photon detectors. Here, we present the key aspects of preparing and testing a silicon photonic quantum chip with an integrated photon source and two-photon interferometer. The most important aspect of an integrated quantum circuit is minimizing loss so that all of the generated photons are detected with the highest possible fidelity. Here, we describe how to perform low-loss edge coupling by using an ultra-high numerical aperture fiber to closely match the mode of the silicon waveguides. By using an optimized fusion splicing recipe, the UHNA fiber is seamlessly interfaced with a standard single-mode fiber. This low-loss coupling allows the measurement of high-fidelity photon production in an integrated silicon ring resonator and the subsequent two-photon interference of the produced photons in a closely integrated Mach-Zehnder interferometer. This paper describes the essential procedures for the preparation and characterization of high-performance and scalable silicon quantum photonic circuits.

Silicon photonic chips have the potential to realize complex integrated quantum systems. Presented here is a method for preparing and testing a silicon photonic chip for quantum measurements.

Silicon photonic chips have the potential to realize complex integrated quantum information processing circuits, including photon sources, qubit ...

Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

Optimized sampling protocols and the development of new wipe materials can be facilitated by standardized measurements of collection efficiency from wipe-sampling. Our approach for sampling trace explosives uses an automated device to control speed, force, and distance during wipe-sampling followed by extraction of collected explosives.

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common ...

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due to their potential applications for future device technologies such as sensors and storage. However, conventional approaches, which usually utilize materials containing magnetic metal ions (or radicals), have a major problem: only a few materials have been found to show the coupling phenomena at room temperature. Recently, we proposed a new approach to achieve room-temperature magnetoelectrics. In contrast to conventional approaches, our alternative proposal focuses on a completely different material, a &#34;liquid crystal&#34;, free from magnetic metal ions. In such liquid crystals, a magnetic field can be utilized to control the orientational state of constituent molecules and the corresponding electric polarization through magnetic anisotropy of the molecules; it is an unprecedented mechanism of the magnetoelectric effect. In this context, this paper provides a protocol to measure ferroelectric properties induced by a magnetic field, that is, the direct magnetoelectric effect, in a liquid crystal. With the method detailed here, we successfully detected magnetically-tuned electric polarization in the chiral smectic C phase of a liquid crystal at room temperature. Taken together with the flexibility of constituent molecules, which directly affects the magnetoelectric responses, the introduced method will serve to allow liquid crystal cells to acquire more functions as room-temperature magnetoelectrics and associated optical materials.

In this report, we present a protocol to examine direct magnetoelectric effects, i.e., induction of ferroelectric polarization by applying magnetic fields, in liquid crystals. This protocol provides a unique approach, supported by the softness of liquid crystals, to achieve room-temperature magnetoelectrics.

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...

A Rapid Method for Modeling a Variable Cycle Engine

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft engines. However, developing VCE requires high costs. Thus, it is essential to build a mathematical model when developing an aircraft engine, which may avoid a large number of real tests and reduce the cost dramatically. Modeling is also crucial in control law development. In this article, based on a graphical simulation environment, a rapid method for modeling a double bypass variable cycle engine using object-oriented modeling technology and modular hierarchical architecture is described. Firstly, the mathematical model of each component is built based on the thermodynamic calculation. Then, a hierarchical engine model is built via the combination of each component mathematical model and the N-R solver module. Finally, the static and dynamic simulations are carried out in the model and the simulation results prove the effectiveness of the modeling method. The VCE model built through this method has the advantages of clear structure and real-time observation.

Here, we present a protocol to build a component-level mathematical model for a variable cycle engine.

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft ...

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...

This protocol presents a detailed procedure for the operation of continuous, micron-sized cryogenic cylindrical and planar liquid jets. When operated as described here, the jet exhibits high laminarity and stability for centimeters. Successful operation of a cryogenic liquid jet in the Rayleigh regime requires a basic understanding of fluid dynamics and thermodynamics at cryogenic temperatures. Theoretical calculations and typical empirical values are provided as a guide to design a comparable system. This report identifies the importance of both cleanliness during cryogenic source assembly and stability of the cryogenic source temperature once liquefied. The system can be used for high repetition rate laser-driven proton acceleration, with an envisioned application in proton therapy. Other applications include laboratory astrophysics, materials science, and next-generation particle accelerators.

This protocol presents the operation and principles of micron-scale cylindrical and planar cryogenic liquid jets. Until now, this system has been used as a high repetition rate target in laser-plasma experiments. Anticipated cross-disciplinary applications range from laboratory astrophysics to material science, and eventually next-generation particle accelerators.

This protocol presents a detailed procedure for the operation of continuous, micron-sized cryogenic cylindrical and planar liquid jets. When operated as ...