Thin Filters Research Articles

High laser fluence ITO coatings utilizing a Fabry-Perot thin film filter to reduce effective absorption.

Laser-induced damage threshold of transparent conductors, such as Indium Tin Oxide (ITO), is limited by their high optical absorption due to free carriers. However, the effective absorption of a transparent conductor thin film can be reduced by an order of magnitude, without changing the electrical characteristics of the film, when placed in a low electric field section of a multilayer coating. A Fabry-Perot thin film interference filter has both high transmittance and low electric field positions, so it is an ideal thin film structure for this application. Although Fabry-Perot interference filters are not known as particularly high laser-induced damage resistant coatings due to their resonant characteristics, a laser-induced damage threshold (LIDT) improvement of up to 8× was observed with this technique compared to single layer ITO coatings fabricated using either radio frequency magnetron sputtering or electron-beam deposition. Additionally, an approximately 4× LIDT improvement for a Fabry-Perot interference filter has been observed by the addition of ITO into the multilayer structure.

Oscillatory microcells connected on a ring by chemical waves.

The dynamics of four coupled microcells with the oscillatory Belousov-Zhabotinsky (BZ) reaction in them is analyzed with the aid of partial differential equations. Identical BZ microcells are coupled in a circle via identical narrow channels containing all the components of the BZ reaction, which is in the stationary excitable state in the channels. Spikes in the BZ microcells generate unidirectional chemical waves in the channels. A thin filter is put in between the end of the channel and the cell. To make coupling between neighboring cells of the inhibitory type, hydrophobic filters are used, which let only Br2 molecules, the inhibitor of the BZ reaction, go through the filter. To simulate excitatory coupling, we use a hypothetical filter that let only HBrO2 molecules, the activator of the BZ reaction, go through it. New dynamic modes found in the described system are compared with the "old" dynamic modes found earlier in the analogous system of the "single point" BZ oscillators coupled in a circle by pulses with time delay. The "new" and "old" dynamic modes found for inhibitory coupling match well, the only difference being much broader regions of multi-rhythmicity in the "new" dynamic modes. For the excitatory type of coupling, in addition to four symmetrical modes of the "old" type, many new asymmetrical modes coexisting with the symmetrical ones have been found. Asymmetrical modes are characterized by the spikes occurring any time within some finite time intervals.

Influence of the electron beams incidence angles on the depth-dose distribution of the irradiated object

To improve the efficiency of radiation polymerization, crosslinking, etc. A method was proposed for a significant decrease in the depth-dose inhomogeneity in a layer under double-sided irradiation by two electron beams: the main beam incident perpendicular to the surface (Θ = 0°) and the additional beam Θ ≠ 0°. To study the possibilities of the proposed method, the deposit depth-doses in the irradiated polyethylene layer were simulated by the Monte Carlo method. The optimal thicknesses of polyethylene layers and the ratio of the intensities of the main and additional beams for different incidence angles Θ of electrons with the energies of 2, 6, 10 MeV were determined. It was shown that the additional use of thin aluminum filters under two-sided irradiation by two beams with optimal parameters reduced the depth-dose inhomogeneity to ≈5 ÷ 6%. In this case, the efficiency of using the energy of the electron beam is ≈ 93%. The influence of the energy spread of the electron beam on the magnitude of the depth-dose inhomogeneity and methods for reducing this influence was discussed.

Inhibition of cAMP‐Phosphodiesterase 4 (PDE4) Induces Salivation in Mice

While exploring potential anti-inflammatory benefits of PDE4 inhibition in a mouse model of bacterial lung infection, we noticed that treatment with the PDE4 inhibitor Piclamilast visibly induced salivation in the animals. Given the predominant role of autonomic nervous system regulation in the control of salivation, and the potential impact of altered autonomics triggered by PDE4 inhibition on our infection model, we have further explored this observation. InKetamine/Xylazine-anesthetized mice, in which saliva production was tracked by the weight increase of thin filter paper strips placed into the mouths of the animals, treatment with PDE4 inhibitors did not induce saliva production per se, but synergized with low doses of the β-adrenoceptor agonist Isoprenaline to induce substantial salivation that was ablated by treatment with the β-blocker Propranolol, but not the mACh-blocker Atropine, and was absent in CFTRΔF508/ΔF508 mice that lack functional CFTR. Conversely, in awake mice, visual scoring (elevated/abnormal salivation=1; no elevated/abnormal salivation=0) indicated that treatment with PDE4 inhibitors was by itself sufficient to induce substantial salivation, which was ablated by treatment with either Propranolol or Atropine, and was also absent in ΔF508-CFTR-mutant mice. Our findings suggest that in anesthetized mice, in which autonomic nervous system regulations are suppressed, inhibition of cAMP degradation by PDE4 within salivary gland cells potentiates the effects of increased cAMP production resulting from β-adrenoceptor activation, and thereby promote the cAMP/PKA-dependent activation of CFTR that promotes saliva secretion. However, in awake mice, PDE4 inhibition acts via an additional mechanism on the autonomic, muscarinic regulation of salivation, likely by affecting neurotransmitter release. In both awake and anesthetized mice, salivation was induced by several structurally distinct PDE4 inhibitors, but not by a PDE3 inhibitor, suggesting that salivation is a class effect of PAN-PDE4 inhibitors. The PDE4 family comprises four PDE4 subtypes, PDE4A to D. Genetic ablation of any individual PDE4 subtype in the respective KO mouse strains did not induce salivation in either awake or anesthetized mice, indicating that salivation must result from the concurrent inactivation of multiple (at least two) PDE4 subtypes. Taken together, our data identify PDE4 as a critical regulator of CFTR function in an in vivo model and suggests a therapeutic potential of PDE4 inhibition to alleviate CFTR hypofunction in cystic fibrosis. In addition, our data reveal a therapeutic potential for PDE4 inhibition in the treatment of dry mouth, a condition frequently associated with drug-, radiation-, or ageing-induced salivary gland dysfunction.

Facile manufacturing of sub-mm thick CNT-based RC filters

CNT-Based RC networks are described with the purpose of showing empirical findings on the influence of the interdigitated electrodes (IDE) spacing, the dispersant compound and the number of deposited layers, on the impedance magnitude and phase of the CNTs. Additionally, we propose use-cases for these networks, applying them to the realization of filters of second order with easily tunable cut-off frequency, and with the inherent advantages of CNTs and printed technologies, rendering them a prime choice for applications where thin and flexible second order filters are necessary.

Image sensor with hybrid emission filter for in vivo fluorescent imaging

AbstractIn this paper, we report a method of fabricating an implantable image sensor equipped a bandpass hybrid filter for highly sensitive fluorescence observation. A hybrid filter that combines an interference filter and an absorption filter enables a high excitation light removal performance in an implantable image sensor that does not use a lens. In this study, a thin hybrid filter was successfully mounted on the image sensor using the transfer method by using a laser lift‐off technique. The transferred filter has no crack. It was demonstrated that the prototype device exhibited high excitation light removal performance and was able to acquire a fluorescent image with high contrast.

Application of laboratory beta radiometry for quantitative indication of radionuclide concentration in plant samples

The aim is to improve the beta-radiometric method of quantitative indication of the content of 90Sr and 137Cs in the counters of plant samples.
 Material and methods. In the Chernobyl exclusion zone (ChEZ) in 2017, 2019, leaves of silver birch, black poplar, common reed, sedge were selected, which were dried, crushed, and used as calculating samples for beta radiometry and spectrometry. For measurements, a combined KRK-1 radiometer and a SEB 01-150 spectrometer beta-radiation energy were used.
 Results. Currently, in plant samples from the ChEZ, the following are widespread: natural 40K, the concentration of which is usually less than 1 % in relation to the concentration of technogenic radionuclides 90Sr+90Y and 137Cs, therefore, when measuring 90Sr and 137Cs, beta radiation of 40K can be ignored. The measurements were carried out without a spectral filter and using a thin molybdenum filter. Without filter – show the count rate of 90Sr+90Y and 137Cs radiation. The filter transmits 2–3.5 % of the low-energy beta radiation of 90Sr and 137Cs and more than 95 % of the high-energy 90Y. The ratio of the count rate of 90Y pulses with and without filter is 2.14. The 90Sr concentration in the samples was determined from the results of measurements of 90Y, and 137Cs – through the fraction of the counting rate, which remains after deducting 90Sr+90Y. Comparison of the concentration of radionuclides measured by the method of beta-radiometry and spectrometry showed no significant difference between the results obtained by the two methods.
 Conclusions. The beta radiometry method for 90Sr and 137Cs provides for measuring the counting rate of beta radiation from counting samples without a spectral filter and using a thin molybdenum filter. Based on the research results, a procedure for calculating the concentration of 90Sr and 137Cs in counting samples of plant leaves was developed

Investigation of Filter Cake Evolution in Carbonate Formation Using Polymer-Based Drilling Fluid.

Drilling fluid and filtrates invasion often alter the near-wellbore flow properties during overbalanced drilling. The utilization of polymeric gels to prevent drilling fluid loss reduces the risk of formation damage caused by this alteration. In this study, the internal and external filter cake evolution by polyacrylamide (PAM) cross-linked with polyethylenimine (PEI) was investigated. The analysis conducted in this study showed that the cross-linked polymer activates and forms a mature gel inside the formation’s pores. Gel also formed a dense uniform structure on the rock’s surface, preventing further fluid loss. A high sealing pressure of up to 1000 psi was achieved, allowing drilling to continue without the need for additional casing string to prevent lost circulation. Moreover, the PAM/PEI formula showed less invasion of filtrate and evolution of a thin shallow internal filter cake that penetrated less than half of the filter disk thickness. In comparison to the full invasion and particle depositions that occurred with the water-based mud (WBM), the PAM/PEI formula is expected to reduce the impact of lost circulation materials (LCMs) on formation damage.

Interaction of lubricants on the rheological and filtration loss properties of water-based drilling fluids

Drilling fluids show significant role in the success of drilling operations of oil and gas well. Lubricating and rheological properties are important for efficient drilling leading to improved oil/gas production. The current work deals with assessing the lubricating properties of 16 different water-based drilling fluids using five lubricants and scrutinizing their consequence on the rheology of the mud, filtration properties and mud cake thickness. Experiments are carried out at 90 °C by hot rolling the drilling fluids. After aging, the rheological, API HPHT filtration loss, and lubricating properties of mud are measured at ambient conditions. The results have been discussed in relation to the effect of lubricants on the recovery performance of oil and gas from reservoir. Increased lubrication provides enhancement in rate of penetration, with improved drilling efficiency into the oil and gas reservoir rock formation. The HPHT filter press test showed permissible fluid loss for all the drilling fluid systems containing lubricants with thin and impermeable filter cake formation. The thin mud cake and less fluid loss into the reservoir indicate less reservoir damage while drilling thus indicating enhanced recovery of oil and gas during production operation.

One-pot facile synthesis and electrochemical evaluation of selenium enriched cobalt selenide nanotube for supercapacitor application

The present study emulates a one-pot facile synthesis of selenium-enriched CoSe nanotube using a chemical bath deposition (CBD) procedure. Schematic incorporation of 3D Ni foam current collectors as substrates for the growth of CoSe–Se nanotubes helped us achieve a binder-less thin film coating. The controlled synthesis of CoSe–Se nanotube was carried out by optimizing the temperature and time of the deposition. CoSe–Se nanotubes were grown on a porous Ni foam substrate using lithium chloride as a shape directing agent. The study found that the one dimensional structure of the nanotubes with porous nature results in an uninterrupted network of electroactive sites. Due to the superior conductivity, the as-fabricated material exhibited excellent rate capability and a higher degree of electrolyte ion diffusion across the CoSe–Se crystal structure. The CoSe–Se@Ni foam electrodes exhibited a specific capacitance of 1750.81 F g−1 at 1 A g−1. The electrode exhibited excellent cycling stability and showed a capacitance retention of 95% after 4000 charge-discharge cycles. Finally, an asymmetric supercapacitor (ASC) device was fabricated with the as-synthesized CoSe–Se@Ni foam electrode as the cathode, activated carbon@Ni foam electrode as the anode, and a thin filter paper separator soaked in 1 M aqueous KOH electrolyte solution. The ASC device showed a specific capacitance value of 106.73 F g−1 at 0.5 A g−1, and achieved an energy density of 37.94 Wh kg−1 at a power density of 475.30 W kg−1. The ASC device was utilized in an extended potential window of 1.6 V. The fabricated device displayed exceptional cycling stability with a capacitance retention of 93% after 5000 charge-discharge cycles.

Towards using high-performance liquid chromatography at home

In order to make high-performance liquid chromatography (HPLC) more widely available at home and in small-scale settings, we have simplified two of its most costly modules, namely the pump and the detector. This should make the setup affordable for home or small laboratory use. A manual HPLC pump was constructed so as to fit into a caulk gun from a local hardware store enabling the generation of 100-150 bar of pressure. In order to limit the pressure drop during the running of a chromatogram, a pulse dampener was developed. We further modified the electrochemical detection (ECD) system so as to use a cheap boron-doped diamond electrode with an overlay of thin filter paper, causing an eluent flow over the electrode by wicking and gravity. Both the pump and the detector are at least ten times cheaper than conventional HPLC modules.Using a home-packed JupiterⓇ Proteo reversed phase capillary column we show how this low-cost HPLC system generates well resolving chromatograms after direct injection of fresh urine. The ECD did not lose its sensitivity during regular use over more than half a year. For homovanillic acid (HVA), which is of medical interest, we measured a linear dynamic range of two orders of magnitude, a detection limit of HVA in the injected sample of 3 μM and a coefficient of variation <10%. The contribution to peak broadening by the detector was much smaller than the contributions by the injector and by the column. After consumption of table olives containing hydroxytyrosol (HT), its metabolite HVA in the corresponding urine could be measured quantitatively. An approach to quantify HT in table olives is presented, as well. This method provides a new tool for investigating physiology of oneself or of dear ones at home.

Evaluation of &lt;i&gt;Pleurotus&lt;/i&gt; as Fluid Loss Control Agent in Synthetic Base Mud for Oil and Gas Drilling Operations

Pleurotus as a fluid loss control additive in synthetic based mud for oil and gas operations was conducted in the laboratory in accordance with API standards using high temperature-high pressure filter press. The effectiveness and compatibility of Pleurotus to synthetic based mud was also evaluated. Its rheological properties were also carried out. Sodium Asphalt Sulfonate was used as a control sample. Synthetic base mud was formulated and the concentrations of 2ppb, 4ppb, 6ppb and 8ppb of Pleurotus were used in four mud formulations with the same materials and in equal concentrations. 4.6ml, 4.0ml, 3.5ml and 3.1ml of fluid loss volumes were obtained respectively. 1mm thick filter cake, with increase in electrical stability was observed. From the laboratory measurement, the optimum effective concentration of Pleurotus to be applied as a fluid loss control agent for fresh non-aqueous mud for field operation is 2ppb which gave the fluid loss volume less than 5ml. The result was compared with the field standard of less than or equal to 5ml fluid loss volume. These results were comparable with control sample and field standard. Also, the thin impermeable filter cake obtained reflects one of the qualities of a good fluid loss control agent. It also showed that Pleurotus contribute very minimal effect on the rheological properties of the synthetic base mud. Improved electrical stability which is the function of emulsion stability confirmed the compatibility property of Pleurotus as fluid loss control additive in the synthetic based mud. The volume of the filtrate improved in geometric progression with the concentrations of the additive applied which summarizes the characteristics of a good fluid loss control agent.

Cold electrons acceleration in TNSA laser‐generated plasma using a low‐contrast fs laser

AbstractThe fs laser facility in Bordeaux, delivering an intensity of 1018 W/cm2 at normal incidence on thin foils, has been used to induce forward electron and ion acceleration in target‐normal‐sheath‐acceleration (TNSA) regime. Micrometric thin foils with different composition, thickness, and electron density, were prepared to promote the charge particle acceleration in the forward direction. The plasma electron and ion emission monitoring were performed on‐line using SiC semiconductor detectors in time‐of‐flight (TOF) configuration and gaf‐chromics films both covered by thin absorber filters. The experiment has permitted to accelerate electrons and protons. A special attention was placed to detect relativistic hot electrons escaping from the plasma and cold electrons returning to the target position. The electron energies of the order of 100 keV and of about 1 keV were detected as representative of hot and cold electrons, respectively. A high cold electron contribution was measured using low‐contrast fs laser, while it is less evident using high‐contrast fs lasers. The charge particle acceleration depends on the laser parameters, irradiation conditions, and target properties, as will be presented and discussed.

Invasive Melanoma: The Treatment-Resistant Skin Cancer with the Deadly Reputation

Although melanoma accounts for less than a tenth of all skin cancers, it is responsible for three quarters of skin cancer deaths. It has a more aggressive nature, tendency to metastasise and is more resistant to anti-cancer therapies than non-melanoma skin cancer. The more common skin malignancies arise from the epidermal keratinocytes but the melanoma arises from the melanocyte, sitting on the dermo-epidermal junction. The difference is the neural crest origin of the melanocyte. Cells of neural crest origin are characterised by being heterogeneous, multipotent, mobile, having a high degree of plasticity and, in development and disease able to demonstrate epidermal to mesenchymal transition. The evolutionary deployment of the neural crest cells allowed early chordate species to transform from thin sessile filter feeders into the more mobile, active, and predatory vertebrates, demonstrating adaptation to a wider range of environmental niches. Mature cells of neural crest origin can also, in certain circumstances, be induced to revert to a precursor, stem cell-like state to access plasticity and immune-modulation. These characteristics can be manipulated to the advantage of the melanoma cell mass to increase tumour invasiveness and progression.

Study of Non-Periodic Pinhole Array Filter for Decreasing High-Order Noise for Compact Holographic Display

The non-periodic pinhole array filtering of a spatial light modulator (SLM) is proposed for filtering the high-order noise and DC noise of a holographic display. Conventionally, DC and high-order noise sources are filtered by a 4f filtering system. Because the 4f filtering system requires a long optical path length, noise filtering is a stumbling block when attempting to realize a compact holographic display. By contrast, the proposed method simply uses a thin filter fabricated by photolithography. In order to verify this concept, we confirmed the feasibility of the filter with a numerical simulation and with a custom-made non-periodic pinhole array filter used in a practical experiment. The proposed method was shown to have the potential to be used in applications ranging from compact wearable devices to table-top holographic displays.

Thermal tuning of arsenic selenide glass thin films and devices.

We present a method of post-deposition tuning of the optical properties of thin film dielectric filters and mirrors containing chalcogenide glass (ChG) layers by thermally adjusting their refractive index. A common challenge associated with the use of ChG films in practical applications is that they suffer from slight run-to-run variations in optical properties resulting from hard-to-control changes in source material and deposition conditions. These variations lead to inconsistencies in optical constants, making the fabrication of devices with prescribed optical properties challenging. In this paper, we present new work that takes advantage of the large variation of a ChG films' refractive index as a function of annealing. We have carried out extensive characterization of the thermal index tuning and thickness change of arsenic selenide (As2Se3) ChG thin films and observed refractive index changes larger than 0.1 in some cases. We show results for refractive index as a function of annealing time and temperature and propose a model to describe this behavior based on bond rearrangement. We apply thermal refractive index tuning to permanently shift the resonance of a Fabry-Perot filter and the cutoff wavelength of a Bragg reflector. The Bragg reflector, consisting of alternating As2Se3 and CaF2 layers, exhibits high reflectance across a ∼550 nm band with only five layers. Modeling results are compared with spectroscopic measurements, demonstrating good agreement.

Experimental study of the relationship between initial single-pass efficiency and structural parameters of honeycomb adsorption filters

An adsorption filter is the main functional component of a portable air cleaner. However, it is not easy to predict the adsorption efficiency of honeycomb adsorption filters using existing methods. Some of the required parameters are difficult to measure, in particular the hydraulic diameter of the adsorbent. In addition, some of the structural factors of honeycomb adsorption filters that affect the efficiency are not considered. Therefore, the relationship between the initial single-pass efficiency and the structural parameters was studied experimentally using benzene at concentrations of 0.4–3 ppm and 2.5–20-mesh activated carbon. The void ratio ranged from 0.293 to 0.919, and the face air velocity was 0.1–1.8 m/s. The air temperature was 25 °C, and the relative humidity was 40%. The results showed that the method can achieve acceptable precision when the void ratio is used instead of the hydraulic diameter of the granular adsorbent in the empirical equation for calculating the initial single-pass efficiency. Other necessary parameters in the empirical formula are the face air velocity and thickness. Moreover, the adsorbent shape and filling rate affect the initial single-pass efficiency, but an acceptable accuracy can be obtained without considering them in the empirical formula. Using a skeleton with loosely arranged cells can reduce the single-pass efficiency. In addition, the adsorption efficiency of a thin honeycomb adsorption filter with a total efficiency of less than approximately 30% can be considered to be the same along the flow channel, regardless of the effects of changes in the concentration.

Sculpting Optical Properties of Thin Film IR Filters through Nanocrystal Synthesis and Additive, Solution Processing

Plasmonic band-stop filters with tunable optical absorbance in the near- and mid-IR are important for wireless communications, bioimaging, and filtering applications. However, their design is const...

P‐117: FLI Structure for R1 Foldable AMOLED Display

A 6.2inch WQHD+ R1 foldable AMOLED display with FLI structure having thin thickness, wide color gamut, high brightness and low reflectivity was obtained. FLI means a structure of RGB emitter, thin film encapsulation, On‐TFE‐Touch and low temperature color filter.

Development of a green multifunctional additive for applications in water-based drilling fluids

Dynamism associated with drilling conditions such as during well completion may necessitate switching between overbalanced drilling and underbalanced drilling in the same drilling operation. One possible way to easily facilitate this is to use appropriate drilling fluid suitable for any drilling condition. A multifunctional drilling fluid additive gives the opportunity to develop drilling fluids that have the same base composition but different functionality. In this study, a novel additive was developed via alkaline extraction and hydrolysis of date pits components in a freezing-defreezing technique. This additive was tested in a water-based bentonite drilling fluid which was characterized in terms of density and filtration properties. The results showed that the drilling fluids containing this novel additive have low filtration properties attributed to products of complete alkaline hydrolysis of fatty acids and amino acids, and the unreacted alkali. The drilling fluid containing the novel additive when neutralized resulted in another drilling fluid of higher filtration properties and lower density. The potential of the un-neutralized drilling fluid to form a thin filter cake of low permeability makes it a suitable candidate for overbalanced drilling while the synergistic effect of both the low density and high filtration property of the neutralized drilling fluid favours its efficacy for underbalanced drilling. The multifunctionality of this novel additive derives from its potential to be used to develop both the overbalanced drilling fluid and underbalanced drilling fluid.