Quartz Disk Research Articles

Optomechanical measurement of a millimeter-sized mechanical oscillator approaching the quantum ground state

Cavity optomechanics is a tool to study the interaction between light and micromechanical motion. Here we observe optomechanical physics in a truly macroscopic oscillator close to the quantum ground state. As the mechanical system, we use a mm-sized piezoelectric quartz disk oscillator. Its motion is coupled to a charge qubit which translates the piezo-induced charge into an effective radiation–pressure interaction between the disk and a microwave cavity. We measure the thermal motion of the lowest mechanical shear mode at 7 MHz down to 30 mK, corresponding to roughly 102 quanta in a 20 mg oscillator. We estimate that with realistic parameters, it is possible to utilize the back-action cooling by the qubit in order to control macroscopic motion by a single Cooper pair. The work opens up opportunities for macroscopic quantum experiments.

Preparation of stable silica surfaces for surface forces measurement.

A surface forces apparatus (SFA) measures the forces between two surfaces as a function of the surface separation distance. It is regarded as an essential tool for studying the interactions between two surfaces. However, sample surfaces used for the conventional SFA measurements have been mostly limited to thin (ca. 2-3 μm) micas, which are coated with silver layers (ca. 50 nm) on their back, due to the requirement of the distance determination by transmission mode optical interferometry called FECO (fringes of equal chromatic order). The FECO method has the advantage of determining the absolute distance, so it should be important to increase the availability of samples other than mica, which is chemically nonreactive and also requires significant efforts for cleaving. Recently, silica sheets have been occasionally used in place of mica, which increases the possibility of surface modification. However, in this case, the silver layer side of the sheet is glued on a cylindrical quartz disc using epoxy resin, which is not stable in organic solvents and can be easily swollen or dissolved. The preparation of substrates more stable under severe conditions, such as in organic solvents, is necessary for extending application of the measurement. In this study, we report an easy method for preparing stable silica layers of ca. 2 μm in thickness deposited on gold layers (41 nm)/silica discs by sputtering, then annealed to enhance the stability. The obtained silica layers were stable and showed no swelling in organic solvents such as ethanol and toluene.

Biosurfactant as an Enhancer of Geologic Carbon Storage: Microbial Modification of Interfacial Tension and Contact Angle in Carbon dioxide/Water/Quartz Systems.

Injecting and storing of carbon dioxide (CO2) in deep geologic formations is considered as one of the promising approaches for geologic carbon storage. Microbial wettability alteration of injected CO2 is expected to occur naturally by microorganisms indigenous to the geologic formation or microorganisms intentionally introduced to increase CO2 storage capacity in the target reservoirs. The question as to the extent of microbial CO2 wettability alteration under reservoir conditions still warrants further investigation. This study investigated the effect of a lipopeptide biosurfactant—surfactin, on interfacial tension (IFT) reduction and contact angle alteration in CO2/water/quartz systems under a laboratory setup simulating in situ reservoir conditions. The temporal shifts in the IFT and the contact angle among CO2, brine, and quartz were monitored for different CO2 phases (3 MPa, 30°C for gaseous CO2; 10 MPa, 28°C for liquid CO2; 10 MPa, 37°C for supercritical CO2) upon cultivation of Bacillus subtilis strain ATCC6633 with induced surfactin secretion activity. Due to the secreted surfactin, the IFT between CO2 and brine decreased: from 49.5 to 30 mN/m, by ∼39% for gaseous CO2; from 28.5 to 13 mN/m, by 54% for liquid CO2; and from 32.5 to 18.5 mN/m, by ∼43% for supercritical CO2, respectively. The contact angle of a CO2 droplet on a quartz disk in brine increased: from 20.5° to 23.2°, by 1.16 times for gaseous CO2; from 18.4° to 61.8°, by 3.36 times for liquid CO2; and from 35.5° to 47.7°, by 1.34 times for supercritical CO2, respectively. With the microbially altered CO2 wettability, improvement in sweep efficiency of injected and displaced CO2 was evaluated using 2-D pore network model simulations; again the increment in sweep efficiency was the greatest in liquid CO2 phase due to the largest reduction in capillary factor. This result provides novel insights as to the role of naturally occurring biosurfactants in CO2 storage and suggests that biostimulation of biosurfactant production may be a feasible technique for enhancement of CO2 storage capacity.

Striation and slickenline development on quartz fault surfaces at crustal conditions: Origin and effect on friction

AbstractFragments of optically flat silica discs embedded in synthetic gouge were deformed to examine the relationship between the development of striations and slickenlines, and deformation mechanisms, conditions, and fault rheology. Experiments were performed under hydrothermal conditions in a rotary shear apparatus at 100°C or 450°C, to shear strains of 2.02 < γ < 8.25. Slip hardening and softening prevail at low and high temperatures, respectively. In recovered samples, disc fragment surfaces are decorated by fine gouge, sometimes arranged in trails, pits, and scratch marks. Prominent grooves—inferred slickenlines—with constant orientation, wavelength <10 μm, and amplitude <0.7 μm are only observed on disc fragments deformed at 450°C. Some parts of the grooves below the original disc fragment surface contain scattered rounded beads of silica ~200 nm diameter. Conversely, close examination of pits in 100°C experiments reveals they contain angular particles <2 μm diameter. The 200 nm diameter crystalline quartz can precipitate at 450°C in only 250 s, well within the time frame of the experiments but precipitation at 100°C would take at least 8 years. No systematic dislocation arrays were observed in the quartz disc fragments, but microfractures are sporadically present. This indicates that at both temperatures brittle failure generated microfractures and microcomminution occurred where gouge particles impacted disc fragment surfaces. These observations suggest formation of silica beads by precipitation from amorphous silica facilitates slip weakening, smoothing of the fault surface parallel to the slip vector, development of undulations perpendicular to the slip vector by a pressure solution creep mechanism, weakening, and maintenance of a constant slip direction.

The Study of a Millimeter to Submillimeter Wave Multiband High-Power Broadband Window

The theory of multilayer microwave window is investigated and applied to design a broadband high-power output window for a Q-band sheet beam traveling wave tube (SBTWT). The multilayer window consists of a c-axis sapphire disc (the geometry axis parallel to optical axis) in the middle and two identical matching quartz discs tightly attached on both sides. It presents a good multiband wideband and high-power performance from millimeter wave to terahertz range. The thermal property is analyzed and shows a more than 60 kW CW operating capability can be reached. The window is manufactured and cold tested shows a −17 dB reflection bandwidth over 15 GHz (34%). The theory analysis, simulation, and cold test present a good consistency.

Biosensor surface attachment of the ovarian cancer biomarker HSP10 via His-tag modification

Herein, we describe a new protocol for the silane-based surface modification of quartz substrates for the immobilization of hexa-histidine-tagged heat shock protein 10. This molecule is an attractive biomarker for the detection of ovarian cancer, particularly for possible early-stage diagnosis. The surface chemistry we have described is used for a study of the interaction between the protein and a novel DNA aptamer via an in-house built acoustic wave sensing platform. Quartz discs were modified with a mixed trichlorosilane adlayer and functionalized with a nickel-NTAL moiety to allow for immobilization of the protein in a correctly-oriented fashion. All layers were characterized by x-ray photoelectron spectroscopy to show successful layer modification. Detection of binding in phosphate buffered saline was determined using the EMPAS, operating at a fundamental frequency of 940MHz. Results regarding the specific binding of the DNA aptamer to the surface-immobilized protein exhibited a significantly smaller signal compared to surfaces without protein, which comparatively yielded much larger frequency shifts. The smaller shift in frequency is attributed to the rigidification of the bulk layer upon interaction between probe and ligand as the overwhelming factor. This rigidification is counteracted by mass loading effects, in which a balance between these two factors is what contributes to the overall smaller frequency shift. Without the binding interaction, the bulk layer does not rigidify, resulting in mass loading being the main contributor to signal, and thus a large frequency shift is seen.

Utilizing a Key Aptamer Structure-Switching Mechanism for the Ultrahigh Frequency Detection of Cocaine.

Aptasensing of small molecules remains a challenge as detection often requires the use of labels or signal amplification methodologies, resulting in both difficult-to-prepare sensor platforms and multistep, complex assays. Furthermore, many aptasensors rely on the binding mechanism or structural changes associated with target capture by the aptameric probe, resulting in a detection scheme customized to each aptamer. It is in this context that we report herein a sensitive cocaine aptasensor that offers both real-time and label-free measurement capabilities. Detection relies on the electromagnetic piezoelectric acoustic sensor (EMPAS) platform. The sensing interface consists of a S-(11-trichlorosilyl-undecanyl)benzenethiosulfonate (BTS) adlayer-coated quartz disc onto which a structure-switching cocaine aptamer (MN6) is immobilized, completing the preparation of the MN6 cocaine aptasensor (M6CA). The EMPAS system has recently been employed as the foundation of a cocaine aptasensor based on a structurally rigid cocaine aptamer variant (MN4), an aptasensor referred to by analogy as M4CA. M6CA represents a significant increase in terms of analytical performance, compared to not only M4CA but also other cocaine aptamer-based sensors that do not rely on signal amplification, producing an apparent K(d) of 27 ± 6 μM and a 0.3 μM detection limit. Remarkably, the latter is in the range of that achieved by cocaine aptasensors relying on signal amplification. Furthermore, M6CA proved to be capable not only of regaining its cocaine-binding ability via simple buffer flow over the sensing interface (i.e., without the necessity to implement an additional regeneration step, such as in the case of M4CA), but also of detecting cocaine in a multicomponent matrix possessing potentially assay-interfering species. Finally, through observation of the distinct shape of its response profiles to cocaine injection, demonstration was made that the EMPAS system in practice offers the possibility to distinguish between the binding mechanisms of structure-switching (MN6) vs rigid (MN4) aptameric probes, an ability that could allow the EMPAS to provide a more universal aptasensing platform than what is ordinarily observed in the literature.

A Novel Strategy for the Synthesis of CeO2/CeF3 Composite Powders with Improved Suspension Stability and Chemical Mechanical Polishing (CMP) Performance

CeO2 is one of the most promising materials applied in chemical mechanical polishing industry. However, due to the high hardness of CeO2, a further surface modification is usually required, especially when polishing a soft substrate, such as fused quartz and optical disk. In this work, we reported a novel process for the synthesis of CeO2/CeF3 composite powders which showed improved suspension stability and CMP properties. Ce2(CO3)3 and HF were employed as the precursor materials for Ce and F, respectively, which were simply milled and annealed at different temperatures to get the composite powders. The results showed that the morphology of the powders changed from microrods to grape-like shapes which had a smaller particle size. And the XRD results confirmed the formation of CeO2/CeF3 composite phases after the HF addition. The suspension stability and CMP property measurements indicated that the change of particle morphologies and the formation of composite structure benefited the polishing process for fused quartz substrate, and a more planar surface was obtained. All these results indicated that the current processing was of great potentials for the synthesis and practical applications of ceria-based CMP slurries.

Sulfate Adsorption onto and Desorption from Silicon Dioxide Films

Sulfuric acid, especially in a mixture with hydrogen peroxide, is a commonly used chemical in the surface preparation of silicon. Removal of adsorbed sulfate based contaminants by DI rinsing is an important step in processing steps using sulfuric acid. Fundamental information on the rate and extent of adsorption and desorption of sulfate on surfaces is very scarce. This presentation will discuss sulfate adsorption onto and desorption from SiO2 surfaces using a quartz crystal microbalance with dissipation monitoring capability (QCM-D). The amount of adsorption of sulfate was estimated from frequency shifts of a SiO2 coated AT-cut quartz crystal. The quartz crystal, with a fundamental frequency of 5 MHz, consists of a quartz disk of 14mm diameter, and gold electrodes that are sputtered on both sides of the quartz disc. The SiO2 coating, 300 nm thick, was deposited by PVD onto the active side of quartz crystals. Figure 1 shows a real time frequency recording of a SiO2 coated crystal exposed to flowing 0.2 M sodium sulfate solution. The frequency and dissipation change were measured for different harmonics of the fundamental crystal frequency at the same time. The divergent overtones and high dissipation factor indicated a “soft” adsorbed layer, rendering the Sauerbrey relation invalid for mass calculation from frequency changes. Hence, a viscoelastic model was used for conversion of frequency changes to mass changes. It can be seen the sulfate adsorption onto and desorption from SiO2 surface happens fairly quickly as marked in the figure. At 22 C, the rate constants of desorption are about 0.06 s-1 and 0.16–0.18 s-1 for flow rates of 0.2 ml/min and 1.0 ml/min respectively. The adsorption isotherm of sulfate is shown in figure 2. The equilibrium adsorption increases linearly with sulfate concentration at the range of 0.1 M to 0.6 M. Figure 1

Response of an electrodeless quartz crystal microbalance in gaseous phase and monitoring adsorption of iodine vapor on zeolitic-imidazolate framework-8 film

In this work, the response of an electrodeless quartz crystal microbalance (EL-QCM) in gaseous phase was investigated by an impedance analysis method. The influence of the gap size, area, position and shape of the electrodes on the resonant and equivalent circuit parameters of the EL-QCM was analyzed and discussed in a modified Butterworth–Van Dyke model. Compared with a conventional QCM, the intensity of resonant peak in EL-QCM is reduced remarkably. An EL-QCM has a quality factor in the order of 105 even at an air gap of 1cm, ensuring an excellent frequency stability of this type of sensor. The excitation electrode can be mounted beside of the center of the quartz disc or outside the detection cell if needed, which offers the convenience in combination with mass and optical measurements. As an example of applications, two EL-QCM sensors in a parallel combination were used to monitor the adsorption processes of iodine vapor on quartz surface and zeolitic-imidazolate framework-8 (ZIF-8) film. The transfer process of iodine between two ZIF-8 films was investigated by the series combination of two EL-QCM sensors.

A true theranostic approach to medicine: Towards tandem sensor detection and removal of endotoxin in blood

Sepsis is one of the leading causes of death around the world. The condition occurs when a local infection overcomes the host natural defense mechanism and suddenly spreads into the circulatory system, triggering a vigorous, self-injurious inflammatory host response. The pathogenesis of sepsis is relatively well known, one of the most potent immuno-activator being bacterial lipopolysaccharide (LPS) – also known as ‘endotoxin’. Tests exist to detect endotoxin in bodily fluids, but are expensive, not necessarily user-friendly and require reporter molecules. In addition, the situation for safe and effective anti-endotoxin therapy is problematical. At the present time, endotoxin removal through cartridge hemoperfusion is one of the better alternatives to combat sepsis. The capability to both measure endotoxemia levels and offer an adapted response treatment in a timely manner is crucial for better management and improved prognosis, but is currently unavailable. In this context, we describe herein preliminary research towards the development of an alternative LPS biosensor and an innovative LPS neutralization cartridge to be eventually combined in an all-integrated configuration for the theranostic, personalized treatment of blood endotoxemia/sepsis. LPS detection is performed in a real-time and label-free manner in full human blood plasma, using ultra-high frequency acoustic wave sensing in combination with ultrathin, oligoethylene glycol-based mixed surface chemistry imposed on piezoelectric quartz discs. Biosensing platforms are functionalized with polymyxin B (PMB), a cyclic peptide antibiotic with high affinity for LPS. Analogous surface modification is used on glass beads for the therapeutic cartridge component of the combined strategy. Incubation of LPS-spiked whole blood with PMB-bead chemistry resulted in a significant decrease in the production of pro-inflammatory TNF-α cytokine. LPS neutralization is discussed in relation to the perturbation of its supramolecular chemistry in solution.

Development of a large-area planar surface-wave plasma source with a cavity launcher driven by a 915 MHz UHF wave

A large-area planar surface-wave plasma (SWP) source driven by a 915 MHz ultrahigh frequency (UHF) wave was developed. To avoid using large, thick dielectric plates as vacuum windows, we propose a cavity launcher consisting of a cylindrical cavity with several small quartz discs at the bottom. Three types of launchers with quartz discs located at different positions were tested to compare their plasma production efficiencies and spatial distributions of electron density. With the optimum launcher, large-area plasma discharges with a radial uniformity within ±10% were obtained in a radius of about 25–30 cm in Ar gas at 8 Pa for incident power in the range 0.5–2.5 kW. The maximum electron density and temperature were approximately (0.95–1.1) × 1011 cm−3 and 1.9–2.0 eV, respectively, as measured by a Langmuir probe located 24 cm below the bottom of the cavity launcher. Using an Ar/NH3 SWP with the optimum launcher, we demonstrated large-area amino-group surface modification of polyurethane sheets. Experimental results indicated that a uniform amino-group modification was achieved over a radius of approximately 40 cm, which is slightly larger than the radial uniformity of the electron density distribution.

摩擦静電気が引き起こす陰極線ルミネセンス

Triboluminescence spectra were measured by means of pin-on-disk method for several samples of natural diamond and a synthetic quartz disk in Ne or N2 gas at pressures between 10 and 105 Pa. At the gas pressure between 10 and 1000 Pa, a blue luminescence was observed besides the gas discharge luminescence due to triboelectricity. The spectrum of cathode-ray luminescence, which was measured by electron bombardment on the same diamond sample, was identical with that of the blue luminescence. The gas pressure dependence of the blue luminescence intensity also supports the model that the blue luminescence was induced by electron impact on the diamond surface in the gas discharge.

Amorphization of quartz by friction: Implication to silica‐gel lubrication of fault surfaces

To understand physico‐chemical processes at real contacts (asperities) on fault surfaces, we conducted pin‐on‐disk friction experiments at room temperature, using single crystalline quartz disks and quartz pins. Velocity weakening from friction coefficientμ ∼ 0.6 to 0.4 was observed under apparent normal stresses of 8–19 (18 > 19), when the slip rate was increased from 0.003 to 2.6 m/s. Frictional surfaces revealed ductile deformation of wear materials. The Raman spectra of frictional tracks showed blue shifts and broadening of quartz main bands, and appearance of new peaks at 490–520 and 610 cm−1. All these features are indicative of pressure‐ and strain‐induced amorphization of quartz. The mapping analyses of Fourier transform infrared (FT‐IR) spectroscopy at room dry conditions suggest selective hydration of wear materials. It is possible that the strained Si‐O‐Si bridges in amorphous silica preferentially react with water to form silica‐gel. In natural fault systems, amorphous materials would be produced at real fault contacts and accumulate over the fault surfaces with displacements. Subsequent hydration would lead to significant reduction of fault strength during slip.

A 3D glass optrode array for optical neural stimulation

This paper presents optical characterization of a first-generation SiO2 optrode array as a set of penetrating waveguides for both optogenetic and infrared (IR) neural stimulation. Fused silica and quartz discs of 3-mm thickness and 50-mm diameter were micromachined to yield 10 × 10 arrays of up to 2-mm long optrodes at a 400-μm pitch; array size, length and spacing may be varied along with the width and tip angle. Light delivery and loss mechanisms through these glass optrodes were characterized. Light in-coupling techniques include using optical fibers and collimated beams. Losses involve Fresnel reflection, coupling, scattering and total internal reflection in the tips. Transmission efficiency was constant in the visible and near-IR range, with the highest value measured as 71% using a 50-μm multi-mode in-coupling fiber butt-coupled to the backplane of the device. Transmittance and output beam profiles of optrodes with different geometries was investigated. Length and tip angle do not affect the amount of output power, but optrode width and tip angle influence the beam size and divergence independently. Finally, array insertion in tissue was performed to demonstrate its robustness for optical access in deep tissue.

An acoustic glucose sensor

In vivo glucose monitoring is required for tighter glycaemic control. This report describes a new approach to construct a miniature implantable device based on a magnetic acoustic resonance sensor (MARS). A ∼600–800nm thick glucose-responsive poly(acrylamide-co-3-acrylamidophenylboronic acid) (poly(acrylamide-co-3-APB)) film was polymerised on the quartz disc (12mm in diameter and 0.25mm thick) of the MARS. The swelling/shrinking of the polymer film induced by the glucose binding to the phenylboronate caused changes in the resonance amplitude of the quartz disc in the MARS. A linear relationship between the response of the MARS and the glucose concentration in the range ∼0–15mM was observed, with the optimum response of the MARS sensor being obtained when the polymer films contained ∼20mol% 3-APB. The MARS glucose sensor also functioned under flow conditions (9μl/min) with a response almost identical to the sensor under static or non-flow conditions. The results suggest that the MARS could offer a promising strategy for developing a small subcutaneously implanted continuous glucose monitor.

Sub-critical stable hydrogen-air premixed laminar flames in micro gaps

Sub-critical burning of lean hydrogen-air mixtures in micro gaps between two quartz disks was investigated both experimentally and numerically. Stationary regimes for different compositions and gap sizes were found when sub-critical flames remained in a stable position relative to the disk surfaces. The burning velocity in the micro gaps was observed to reach values much larger than the laminar burning velocity. A reaction-diffusion numerical model was proposed to corroborate experimental results. Different factors, such as boundary conditions for velocity, irradiation of the disk surfaces contacting the gas, and an increase in the chemical reaction rate near disk surfaces were modeled numerically in order to explain the increase in burning velocities. The best correlation between the numerical results and experimental data was observed in the scenario proposing as increased chemical reaction rate near the disk surfaces. Numerical simulations also showed that for large flame front velocities and wider sub-critical gaps, the flame front becomes unstable. The reason for this instability is the asynchronization of the combustion near the disk surfaces and the subsequent turbulization of the flame.

Laser-assisted fabrication of highly viscous alginate microsphere

Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

Study of the Torsional Effect of a Rectangular Quartz Disc

The torsional effect of a rectangular piezoelectric quartz is studied in the article. Using the anisotropic elasticity and Maxwell electromagnetic theory, the stress field and electrostatic field is founded, and then by the Finite Element Method the distribution of the electric field in the piezoelectric body is obtained. Based on theoretical analysis of the bound charge distribution, the measuring electrodes are effectively disposed on the surfaces of the piezoelectric wafers. The theoretical and experimental results show that the measurement charge is linear with the torque. The research will provide the basis for the torque measuring technique.

Metallic Foil-Assisted Laser Cell Printing

Laser direct-write technology such as modified laser-induced forward transfer (LIFT) is emerging as a revolutionary technology for biological construct fabrication. While many modified LIFT-based cell direct writing successes have been achieved, possible process-induced cell injury and death is still a big hurdle for modified LIFT-based cell direct writing to be a viable technology. The objective of this study is to propose metallic foil-assisted LIFT using a four-layer structure to achieve better droplet size control and increase cell viability in direct writing of human colon cancer cells (HT-29). The proposed four layers include a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a cell suspension layer. The bubble formation-induced stress wave is responsible for droplet formation. It is found that the proposed metallic foil-assisted LIFT approach is an effective cell direct-write technology and provides better printing resolution and high post-transfer cell viability when compared with other conventional modified LIFT technologies such as matrix-assisted pulsed-laser evaporation direct-write; at the same time, the possible contamination from the laser energy absorbing material is minimized using a metallic foil.