Hole Pattern Research Articles

High-performance glass filters for capturing and culturing circulating tumor cells and cancer-associated fibroblasts

Various liquid biopsy methods have been developed for the non-invasive and early detection of diseases. In particular, the detection of circulating tumor cells (CTCs) and cancer-associated fibroblasts (CAFs) in blood has been receiving a great deal of attention. We have been developing systems and materials to facilitate such liquid biopsies. In this study, we further developed glass filters (with various patterns of holes, pitches, and non-adhesive coating) that can capture CTCs, but not white blood cells. We optimized the glass filters to capture CTCs, and demonstrated that they could be used to detect CTCs from lung cancer patients. We also used the optimized glass filters for detecting CAFs. Additionally, we further developed a system for visualizing the captured cells on the glass filters. Finally, we demonstrated that we could directly culture the captured cells on the glass filters. Based on these results, our high-performance glass filters appear to be useful for capturing and culturing CTCs and CAFs for further examinations.

High-speed mid-wave infrared holey photodetectors

We demonstrate high-speed mid-wave infrared photoconductive detectors leveraging a lattice-mismatched, epitaxially grown InSb absorber material patterned with nanometer-scale hole arrays. We show that the nano-scale hole patterns allow for post-growth control over the detector response time by introducing recombination surfaces to increase non-radiative recombination. The photoconductive pixels are integrated into a microwave coplanar waveguide for high frequency characterization. The detector response is characterized as a function of temperature and hole-array dimensions. We show a detector response with characteristic time scales of tens of picoseconds and bandwidths up to 7 GHz at room temperature. The presented detectors offer a mechanism for engineering response times in long wavelength detectors for potential applications in high-speed sensing/imaging, free-space communication, ranging, or dual-comb spectroscopy.

Impact of H2-enriched natural gas on pollutant emissions from domestic condensing boilers: numerical simulations of the combustion chamber

The addition of green hydrogen to the gas mixture feeding domestic boilers may help the ecological transition of the residential sector. However, there are concerns about the combustion process as hydrogen shows power density and reactivity that are much different than those of natural gas. In this work, we perform three-dimensional simulations with detailed kinetics to describe and comprehend the combustion process in a real modern boiler, equipped with a perforated premixed burner (presenting a pattern of small holes and slits), with the purpose also to evaluate the impact of green hydrogen. The flame structure is complex and characterized by the interaction of flames exiting from neighbor holes and slits; these flames may merge and lead to very intense flames, especially at high flow rates. The presence of a flow distributor, upstream of the burner, induces different velocities at the holes and slits, ultimately affecting the morphology, propagation and interactions of the flames. This behavior is observed for all investigated H2 concentrations, i.e., up to 50% by vol. The model is validated against available measurements of carbon monoxide and nitric oxides in flue gases, which both indicate very satisfactory predictions. More specifically, the addition of green H2 has a beneficial effect on both CO and NO emissions. More specifically the CO emissions at the nominal power are observed to diminish from 154 to 18 ppm when shifting from 0 to 50% H2 in the fuel mixture, while NO emissions decrease from 20 to only 5 ppm. This latter reduction is a surprising and encouraging result; the reason is due to the fact that the addition of hydrogen in the fuel mixture leads naturally to more dilute operating conditions in a condensing boiler. We believe that the proposed model represents a valid tool to explore strategies to improve the combustion process with alternative fuels.

Two-photon shape-modulated maskless lithography of positive photoresist of S1813

The authors systematically investigated influence factors for two-photon maskless lithography of S1813 photoresist. A trench with a width of 155 nm, about 1/5 of the laser wavelength, was fabricated by accurate tuning the scanning speed. Two-photon shape-modulated maskless lithography, a method which employs different combined scanning and exposing approaches was proposed and studied. The patterns of rectangle, parallelogram, rice grain, arc, and “x” letter, and the quatrefoil hole patterns with different shape hearts, were all fabricated by using this method. This work is a protocol for lithography of S1813 photoresist with a high spatial resolution and flexibility. The fabricated trenches and diverse micro/nano patterns can be applied in the fabrication of integrated circuits, metamaterials structures, and SERS and biosensor substrates. This work will be conducive to the development and application of the two-photon maskless lithography of S1813.

Process optimization of contact hole patterns via a simulated annealing algorithm in extreme ultraviolet lithography.

The critical dimension (CD), roughness, and sensitivity are extremely significant indicators for evaluating the imaging performance of photoresists in extreme ultraviolet lithography. As the CD gradually shrinks, tighter indicator control is required for high fidelity imaging. However, current research primarily focuses on the optimization of one indicator of one-dimensional line patterns, and little attention has been paid to two-dimensional patterns. Here, we report an image quality optimization method of two-dimensional contact holes. This method takes horizontal and vertical contact widths, contact edge roughness, and sensitivity as evaluation indicators, and uses machine learning to establish the corresponding relationship between process parameters and each indicator. Then, the simulated annealing algorithm is applied to search for the optimal process parameters, and finally, a set of process parameters with optimum image quality is obtained. Rigorous imaging results of lithography demonstrate that this method has very high optimization accuracy and can improve the overall performance of the device, dramatically accelerating the development of the lithography process.

High aspect ratio arrays of Si nano-pillars using displacement Talbot lithography and gas-MacEtch

Structuring Si in arrays of vertical high aspect ratio pillars, ranging from nanoscale to macroscale feature dimensions, is essential for producing functional interfaces for many applications. Arrays of silicon 3D nanostructures are needed to realize photonic and phononic crystals, waveguides, metalenses, X-ray wavefront sensors, detectors. In particular, arrays of Si nanopillars are used as bio-interfaces in neural activity recording, cell culture, microfluidics, sensing and on-chip manipulation. Here, we demonstrate a strategy for realizing arrays of protruding sharp Si nanopillars, using displacement Talbot lithography combined with metal-assisted chemical etching (MacEtch) in gas phase. Such combination enables reliable and low cost pathway for fabrication of ordered nanopillars arrays on large scale. With the double exposure of a linear grating mask in orthogonal orientations and the lift-off technique, we realized a catalyst pattern of holes in a Pt thin film with a period of 1 μm and hole diameter in the range of 100–250 nm. MacEtch in gas phase by using vapor HF and oxygen from air allows to etch arrays of protruding Si nanopillars 200 nm-thick and aspect ratio in the range of 200 (pillar height/width) with an etching rate up to 1 μm/min. Gas-MacEtch has the advantage of no capillary stiction, no ion beam damage of the Si substrate, nanometric resolution and high fidelity of pattern transfer. In combination with controlled uniformity of feature size on large area, spatial frequency doubling and high resolution of Talbot lithography, the proposed method is an easy-to-scale-up processing that can support the fabrication of Si pillars arrays for many valuable applications both at micro and nano-scale.

Range-Division Multiplexing for MIMO OFDM Joint Radar and Communications

An orthogonal frequency-division multiplexing (OFDM) waveform enables simultaneous radar sensing and communications. In the multiple-input multiple-output (MIMO) case with several transmit (Tx) antennas, multiplexing the transmit signals is usually implemented using equidistant subcarrier interleaving (ESI), thus allowing the separation of the transmit signals in frequency domain. In this work, a multiplexing technique denoted as range-division multiplexing (RDMult) is analyzed, which allows separating signals radiated by different Tx antennas along the range axis of a range-Doppler map. This work also investigates the effects of RDMult on the communication task. It turns out that RDMult heavily distorts the channel statistics by introducing a repetitive pattern of deep fading holes, which severely distort the transmission of data. To combat this issue, this work proposes a communication system especially designed for RDMult, including methods for data estimation, channel estimation and synchronization. Simulations confirm the effectiveness of these concepts in terms of bit error ratio (BER) performance.

Stochastic defect generation depending on tetraalkylhydroxide aqueous developers in extreme ultraviolet lithography

Patterning targets in leading-edge technologies such as extreme ultraviolet lithography (EUVL) are starting to push present photoresist materials (e.g. chemical amplification resists) to their physical limits. The appearance of randomly occurring (stochastic) photoresist-based defects in these stringent patterning targets has become one of the main concerns in EUVL. To obtain possible clues to understanding these stochastic defects, the effect of developer solutions (alkyl chain length of tetraalkylammonium hydroxide) on stochastic defects was investigated. This paper was built on our previous work in which we investigated the dissolution dynamics of three types of typical EUV photoresist processed in developer solutions with different alkyl chain lengths. Using the same materials, we found from EUV patterning experiments focusing on contact hole (CH) patterns that the long-alkyl-chain developer solution, i.e. tetrabutylammonium hydroxide, was effective in mitigating stochastic defects in acryl-type and hybrid-type photoresists (the latter being more commonly utilized for EUVL). (147/150)

Numerical study of perforated steel plate shear walls in staggered pattern

Steel plate shear walls (SPSW) consist of steel plates that are directly connected to columns and beams. The steel plate used as the filler is a thin and slender. One option to reduce the steel plate capacity is to provide perforations in the web plate. In this study, the parameters analysed were the influence of the perforation area on the arrangement of the staggered hole patterns on the steel plate panel. This study uses a numerical method. The result of the research is an analysis that explains the relationship between the percentage of perforation area on the load capacity and the stiffness degradation of the steel plate shear walls. The steel plate model is given a circular perforation with a diameter of 50 mm. The specimens were analysed at different number of perforations with a plate thickness of 1 and 2 mm. The results showed that every enhancement number of perforations, the load capacity and elastic stiffness will decrease. Changing the plate thickness from 2 mm to 1 mm, the load capacity also decreases. The initial stress distribution occurs on the diagonal side of the shear wall plate and then spreads to all parts of the shear wall plate.

Numerical evaluation of a new impingement cooling scheme with a separate return-channel applied to turbine blade leading edge

The turbine blade leading edge is imposed with large heat load due to the flow stagnation effect. Jet impingement cooling is widely used to keep blade leading edge below critical metal temperature. However, accumulated crossflow deteriorates jet-flow penetration and subsequently reduces impingement effectiveness. This study introduces a novel impingement-jet cooling scheme with a separate return-channel to reduce the effect of crossflow by extracting the spent flow upwards. In addition, the swirling flow generated inside the return-channel further augments heat transfer. The effects of different return hole patterns and outflow paths are investigated through Computational Fluid Dynamics (CFD) method based on the BSL turbulence model. The effects of return hole pattern and coolant outflow path are investigated and evaluated. The numerical results prove that introduction of the return-channel has improved area-averaged Nu on the target surface significantly compared to the baseline value. The inline pattern performs better than the staggered pattern within the channels with single outlet in the return-channel. However, with outlets in both the impingement channel and the return-channel, the heat-transfer effects of different return patterns are insignificant.

Fabrication of Freestanding Double-sided Through-hole Electrode Films using Imprint Technique

Recently, flexible electronic devices such as printed electronics have attracted attention. Interposers are required to flexibly connect circuit devices. However, most conventional interposers are not flexible because they are composed of silicon or glass substrates. To solve this problem, we developed a manufacturing process for flexible interposers. We used photolithography to fabricate columnar master molds with diameters of 10 μm and 20 μm. After applying a release agent to the master molds, hole patterns were produced using UV nanoimprint lithography. The holes were filled with silver ink. The flexible interposer was then completed.

Effect of Alternative Developer Solutions on EUVL Patterning

This work explores the application of alternative developer solutions (“developers”) with the aim of understanding their potential effectivity in the reduction of resist-based stochastic pattern defects (or “stochastic defects”) in extreme ultraviolet lithography (EUVL). Specifically, the application of a quaternary ammonium hydroxide type aqueous developer; ethyltrimethylammonium hydroxide (ETMAH) in comparison to the industry de facto standard aqueous alkali tetramethylammonium hydroxide (TMAH) developer was investigated. Focusing on EUV exposed contact hole (CH) patterns on a typical chemically amplified resist (CAR), the effect of these developers on stochastic defects were assessed. As a result, patterning investigations showed that the lithographic performance of the CAR developed in ETMAH is comparable to the those obtained with TMAH. In situ resist dissolution analysis using the high-speed atomic force microscope (HS-AFM) confirms this as it showed that the rate of CH formation during resist dissolution in both developers are relatively the same. Moreover, it was also understood that compared to the commonly used alkali developer concentration of 0.26N, a lower ETMAH developer concentration of 0.20N resulted in stochastic defect margin improvement, while maintaining lithographic performance. In situ resist dissolution analysis showed an obvious slowing down of CH pattern formation rate at 0.20N concentration, suggesting the possibility that of over-dissolution at the higher concentration condition, translating to an increase in merging CH defects. The results from this study show the advantages of further pursuing optimal developers for EUVL. This is especially significant as these findings indicate how optimal developers mitigate resist-based stochastic defects while maintaining lithographic performance.

Boosting the performance of Zn-air cells by spinel catalysts with bimodal pore structure and gill filament configuration

Spinel oxides with specific morphology are importantly multifunctional materials for various applications. Here we report various morphological spinel oxides with one and two-modal pore size structures. The surface microstructure, phase composition, specific surface areas and electrocatalytic OER/ORR activities are examined. The results reveal that the bicomponent (NiCo2O4 and Co3O4) spinel exhibits a bimodal pore size distribution, high specific surface area, good OER activity (an overpotential of 313 mV at 10 mA cm−2Geo) and low Tafel slope of 73.1 mV dec−1. The Co3O4 component presents a perforated sheet morphology similar to an ancient window configuration with regular hole patterns, which benefits for mass transfer and O2 bubble detachment. By comparison, the single-component NiCo2O4 spinel having the morphology of more open self-assembled nanoneedle spheres or nanorod clusters, similar to the configuration of fish gill filaments, shows better ORR activities. The morphology, similar to the fish gills, can readily capture dissolved oxygen molecules from the film electrolyte at the three-phase interface and improve ORR performance. In addition, calcination temperatures also significantly affect pore structure, surface areas, and electrocatalytic activities. Finally, small Lab size Zn-air cells are assembled using thin flexible air electrodes with the self-assembled nanoneedle NiCo2O4 catalysts. Electrochemical charging-discharging performance and cycling durability are evaluated.

PO48 Presentation Time: 10:00 AM: Clinical Implementation of an In-House Made Perineal Template for Low Dose Rate Prostate Brachytherapy Treatment

<h3>Purpose</h3> An in-house perineal needle-template device was developed to improve the interactive¹ low-dose-rate (LDR) brachytherapy treatment planning process for patients with small prostate volume size. One of the side effects of external beam radiation and androgen deprivation therapies is the significant reduction of the prostate gland volume (target) which can be challenging to plan with a standard 5mm hole spacing template. The new perineal needle template (new template) has additional rows with holes placed in a 2.5mm off-set grid pattern which provided more hole locations to place seeds inside the small prostate periphery region for a more conformal plan while meeting all dosimetric planning goals. <h3>Methods and Materials</h3> Thirty patients with different prostate gland volumes size were selected for this study. These thirty patients received either external beam radiation alone or external radiation combined with androgen deprivation therapy. Patients had LDR interactive planning performed using the new template, BARD I-125 seed model STM1251 (USA, IL), BARD QuickLink Delivery System for the seed train assembly, Oncentra - Prostate (Elekta, Sweden) for the treatment planning software (TPS) and the B-K Medical Ultrasound 3000 (USA, MA) for the internal organs imaging. On implant day (DAY 0), the radiation oncologist (physician) contoured target, urethra and rectum on TPS. The medical physicist proceeded to start the planning on the TPS using the inverse planning option to create plan and dose volume histogram (DVH) as the first iteration. Then, manually adjusted and customized the seeds locations with the MD input for a final DVH evaluation in order to proceed and deliver the implant. The AAPM TG-64² dosimetric guidelines were followed and reported. All patients had CT and MRI imaging studies performed approximately 30 days after the implant for a DAY 30 post implant evaluation. Using the Oncentra TPS, both imaging studies were fused, and the prostate, urethra and rectum were contoured. The implanted seeds were registered, and the DAY 0 prescription was used for the post-plan evaluation following the AAPM TG-64 dosimetric guidelines. <h3>Results</h3> Thirty patients were successfully treated using the new template. The new template was modeled in TPS and the ultrasound system. The new template did not affect the calculating time in the TPS and the increased amount of hole locations provided more options for an easier manual optimization "tweaking" to achieve a final plan, especially in the apex location where the target tapers down in size. Initially, physician adaptation to the new template was challenging for the first few cases but rapidly improved as the physician became more familiar with the new hole patterns. <h3>Conclusion</h3> We have successfully designed, built and implemented a new template for brachytherapy LDR treatments of small sizes targets (≤20 cc). The new template has provided a viable option to implant the seeds inside or closer to the target periphery thus improving the interactive planning process significantly.

A novel leakage behavior characterization model of hole pattern seal and its mechanism analysis

A novel leakage behavior characterization model of hole pattern seal and its mechanism analysis

Uniform impingement heat transfer distribution in corrugated channel with an anti-crossflow-wing

For a further improvement of impingement jet array heat transfer in a corrugated channel, a wing-shaped structure design is proposed to weaken crossflow degradation. The naphthalene sublimation method was used to measure local heat/mass transfer distributions in the present study. Pressure drop characteristics were examined through pressure measurements. Detailed flow structures were analyzed through numerical simulations. In order to validate the superiority of the current wing structure, it was compared with the impingement heat transfer values from a typical rectangular channel and a conventional corrugated channel. The hole diameter-based Reynolds number was fixed to 10,000. The impingement distance and spacing between holes were h/d = 1 and s/d = 5, respectively. The hole patterns were designed to be in-lined in all cases. As the wing structure was added to the corrugated channel, the impingement supply flows of downstream holes became axisymmetric. The wing structure noticeably suppressed the re-entry flow from the corrugated channel back into the main/impingement channel, particularly under the downstream row of impingement holes. As a result, the overall area-averaged Sherwood number increased by about 6.4%, and the heat transfer non-uniformity in the streamwise direction was significantly reduced.

Investigation of the effects of passive pre-chamber nozzle pattern and ignition system on engine performance and emissions

The impact of passive pre-chamber (PC) internal volume, nozzle hole pattern (i.e. with and without a central axial nozzle), and PC igniter plug type on performance and emissions was investigated in an optically accessible, single-cylinder, gasoline research engine. The two PC igniter plugs investigated were a conventional inductive coil spark plug and a nanosecond repetitively pulsed (NRP) plasma discharge system previously demonstrated to accelerate early flame propagation. The baseline PC design featured a funnel shaped internal volume with a PC tip that contained six radial nozzles and a larger central axial nozzle. Two additional PC tip geometries were evaluated where either the baseline internal volume was increased or the axial nozzle was removed and the radial nozzle diameters were increased. A sweep of charge equivalence ratios ( ϕ) from nearly stoichiometric to the lean limit was performed for a fixed engine speed (1300 revolutions per minute), and engine load (3.5 bar gross indicated mean effective pressure). Time-resolved PC and main chamber (MC) pressure data as well as MC emissions data were collected to analyze engine performance and emissions characteristics. Combustion in the MC was further investigated using high-speed excited methylidyne radical (CH*) chemiluminescence imaging. Collected results highlighted that while all PC tips and ignition systems exhibited similar performance and emissions down to ϕ = 0.8, relevant differences in thermal efficiency and emissions for leaner charge mixtures were observed, with the results highly dependent on the nozzle pattern and ignition system. Major deviations were correlated to preferential de-pressurization of the PC through the axial nozzle for lean conditions that was not observed for mixture conditions closer to stoichiometric. Results show that a combination of radial and axial nozzle patterns in the PC extended lean-stability limits at the low-load condition evaluated. Further benefits were observed with the use of NRP ignition systems due to faster combustion within the PC volume provided that the volume was sufficiently large.

An Asymptotic Energy Equation for Modelling Thermo Fluid Dynamics in the Optical Fibre Drawing Process

Microstructured optical fibres (MOFs) are fibres that contain an array of air holes that runs through the whole fibre length. The hole pattern of these fibres can be customized to manufacture optical devices for different applications ranging from high-power energy transmission equipment to telecommunications and optical sensors. During the drawing process, the size of the preform is greatly scaled down and the original hole pattern result might be modified, potentially leading to unwanted optical effects. Because only a few parameters can be controlled during the fabrication process, mathematical models that can accurately describe the fibre drawing process are highly desirable, being powerful predictive tools that are significantly cheaper than costly experiments. In this manuscript, we derive a new asymptotic energy equation for the drawing process of a single annular capillary and couple it with existing asymptotic mass, momentum, and evolution equations. The whole asymptotic model only exploits the small aspect ratio of a capillary and relies on neither a fitting procedure nor on any empirical adjustable parameters. The numerical results of the simplified model are in good accordance with experimental data available in the literature both without inner pressurization and when internal pressure is applied. Although valid only for annular capillaries, the present model can provide important insights towards understanding the MOF manufacturing process and improving less detailed approaches for more complicated geometries.

(Invited) 3D Electrode Architectures for High Power and High Energy Lithium-Ion Battery Operation - Recent Approaches and Process Upscaling

During the next decades, combustion driven cars will be completely replaced by electrical vehicles (EVs) and it seems quite obvious that liquid electrolyte lithium-ion batteries (LIBs) will be the dominating energy storage system for the next at least 5 to 10 years. As a consequence, in Europe numerous Gigafactories have recently been planned with this state of technology. However, the current lithium-ion battery technology suffers so far from some restrictions like the inability to combine high power and high energy operations at the same time. This limitation is mainly attributed to the cathode architecture and respective mass loading. In addition, the further demand for a significantly enhanced fast charging mainly requires an optimization of the anode design flanked by a high areal capacity. Advanced 3D electrode architectures based on a thick film electrode concept seem to be the most promising approach to overcome the current limitations in battery performances. However, respective technology innovations need to provide a high compatibility grade to existing manufacturing routes in order to enable the required integration in existing and planned factories. For so-called “generation 3” materials, i.e., nickel-rich lithium nickel manganese cobalt oxide (NMC) cathode and silicon-based anode materials, structuring technologies using cutting edge ultrafast high power lasers, are being developed in order to manufacture 3D electrode architectures with high areal capacity. Multibeam laser processing using diffractive optical elements and dual scanner approaches were established in order to enable high processing speeds in roll-to-roll electrode handling systems. The technology readiness level (TRL 6) is demonstrated for pouch cells geometries. For water-based NMC 622 and silicon-graphite composites the laser structuring process was developed. Different structures including hole, grid, and line patterns, were studied regarding their impact on electrochemical performances such as high-rate capability and cell lifetime. Lithium concentration profiles of unstructured and structured electrodes were studied post mortem using laser-induced breakdown spectroscopy (LIBS) in order to evaluate lithium intercalation/deintercalation efficiencies and detect possible cell degradation processes. In comparison to unstructured electrodes, 3D electrodes could hereby always be identified as superior: unstructured thick film electrodes show a significant drop in capacity retention for high power operation and tend to form hot spots acting as starting point for cell failure. The upscaling process is flanked by a further improvement of electrode design. For this purpose very recently laser induced forward transfer (LIFT) is applied as printing technology to draw new concepts for sophisticated model electrode architectures with advanced electrochemical performances. Finally, the micro-/nano-scaled texturing of current collectors and separator material is discussed as further possible approaches for boosting the electrochemical performances of LIB pouch cells.

Patient-specific needle guidance templates drilled intraprocedurally for image guided intervention: feasibility study in swine.

Thermal ablation of large tumors may benefit from simultaneous placement of multiple needles, but accurate placement becomes challenging as the number of needles increases. The aim of this work was to evaluate use of personalized needle guidance grid templates based on intraprocedural CT and fabricated at the point of care to implement ablation treatment plans with multiple needles in vivo. A plastic frame was designed to hold two parallel plastic guide plates in a rigid relationship, fixed over the abdomen by a mounting arm. Steel ball targets (1.5mm) were implanted under ultrasound in the livers of two domestic swine under general anesthesia. Following breath-hold CT of the subject and frame, the targets and frame were identified using customized 3D Slicer-based planning software. Multiple needle trajectories targeting the balls were planned, including complex off-plane trajectories. A machining program for drilling the hole pattern corresponding to the planned needle trajectories was generated. The pattern was drilled in the two plates with a numerical-controlled milling machine in the suite. The plates were attached to the frame and needles passed through the paired holes to the calculated depth. Placement accuracy was defined as needle tip-to-target distance on post-placement CT. The planning process and manufacturing required approximately 6 and 15min, respectively. Needles were rapidly inserted (n = 11) to the target points without complications or traversing nontarget anatomy. The mean needle tip-to-target distance error was 3.4 ± 2.2, range 0-7mm. Rapid and accurate needle placement was feasible using a subject-specific, custom-drilled, needle guidance grid template fabricated intraprocedurally. Targeting accuracy and performance were similar to more complex and expensive tracking systems which may enable accurate intraprocedural implementation of treatment plans in the liver or other organs. This may be of value in complex ablation cases or in areas where more advanced guidance systems are not available.