Channel Surface Research Articles

Scalable Photonic Nose Development through Corona Phase Molecular Recognition.

Breath sensors promise early disease diagnosis through noninvasive, rapid analysis, but have struggled to reach clinical use due to challenges in scalability and multivariate data extraction. The current breath sensor design necessitates various channel materials and surface functionalization methods, which delays the process. Additionally, the limited options for channel materials that provide optimum sensitivity and selectivity further restrict the array size to a maximum of only 10 to 20 channels. To address these limitations, we propose a breath sensing array design process based on Corona Phase Molecular Recognition (CoPhMoRe), which enables the creation of an expansive library of nanoparticle interfaces and broad fingerprints for multiple analytes in the breath. Although CoPhMoRe has predominantly been utilized for liquid-phase sensing, its recent application to gas-phase sensing has shown significant potential for breath sensing. We introduce the recent demonstrations in the field and present the concept of a CoPhMoRe-based photonic-nose sensor array, leveraging fluorescent nanomaterials such as near-infrared single-walled carbon nanotubes. Additionally, we identified four critical milestones for translating CoPhMoRe into breath sensors for practical clinical applications.

Application of oscillating elastic surfaces for heat transfer enhancement from heat dissipating electronic chips

The present study investigates the possibility of heat transfer enhancement from discrete heat sources by an oscillating elastic surface. The three liquid cooled heat sources are located on the bottom surface of a rectangular channel and are influenced by oscillation of the upper surface. Finite element simulations are carried out at several Reynolds numbers in the laminar flow regime for two different cases of oscillation by cosine and step loads with various periods and amplitudes. It is observed that oscillation of the channel surface alters the direction of the pressure gradient and causes backflow and several vortices along the channel. It also leads to the thermal boundary layer disturbance and flow acceleration on the heat sources and consequently intensifies the heat transfer. Results indicate that reducing the period of the oscillations improves the flow mixing and thus increases the heat transfer rate to an optimum value. Further decrease in the period has a reverse effect on the heat transfer enhancement. Maximum heat transfer enhancement of 223.4 %, 162.2 %, 137.8 %, and 150.5 % are obtained for Reynolds numbers of 200, 600, 1000, and 1400, respectively. It is worth mentioning that the heat transfer enhancement is achieved at the expense of a considerable pressure drop increase. The overall performance factor implies that the heat transfer enhancement dominates the pressure drop increase only at low amplitudes and periods of oscillations. Comparison between the cosine and step loads reveals that the cosine and step forces exhibit better heat transfer performance at low and high periods, respectively.

Enhanced Electrical Performance of InAs Nanowire Field-Effect Transistors Based on the Y2O3 Isolation Layer.

Nanowire (NW) field-effect transistors (FETs) have great potential in next-generation integrated circuits. InAs NWs are suitable for N-type transistors because of their excellent electrical properties. However, unlike the Si/SiO2 system, the loose and defective native oxide of InAs is unable to passivate the channel surface and serve as an efficient isolation layer (IL) in the gate stack. Here, we, for the first time, demonstrate that using a stable dielectric Y2O3 to replace the native oxide IL can effectively passivate the NW surface, isolate the channel surface from high-k HfO2, and improve the electrical properties of InAs NW FETs significantly. First, top-gate devices with Y2O3 IL outperform the devices with native oxide or chemically generated oxide of InAs as the IL, exhibiting a small subthreshold swing (SS) of 77 mV/dec, a large on-off ratio, a high field-effect mobility (μFE) of 1845 cm2/V·s, and an extremely low interface trap density (Dit) of 9.1 × 1011 eV-1 cm-2. Double-gate FETs with Y2O3 IL also show excellent gate control (drain-induced barrier lowering (DIBL) down to 35 mV/V) and a high μFE of 2711 cm2/V·s (the highest in the multigate structure). In addition, InAs NW FETs with Y2O3 IL show greater stability after long-term air exposure than those with native oxide IL, demonstrating retained on-off ratio, DIBL, transconductance, and even smaller SS (from 89 to 77 mV/dec). Finally, the results of low-temperature measurement suggest that Y2O3 IL can effectively improve interface qualities. Our results indicate that Y2O3/HfO2 InAs NW FETs have great potential in digital units of integrated circuits for future nodes. Our strategy for improving the interface between InAs NW and the dielectric layer is also valuable for other III-V NW devices.

Application of liquid metal driven-abrasive flow to material removal for the inner surface of channel

Gallium-based eutectic liquid metal alloys possess unique properties such as deformability, high electrical conductivity, and low vapor pressure. These characteristics have generated significant interest in their application for stretchable electronics and microelectromechanical systems (MEMS). Precise manipulation of liquid metal within electrolytes is essential to meet specific functional requirements. This study investigates the electrostatic manipulation of liquid metal in an alkaline solution with abrasives for material removal from the inner surfaces of flow channels. The polarization of the double layer at the gallium‑indium alloy and electrolyte interface is analyzed, elucidating the principle of electrolyte propulsion via continuous electrowetting. A theoretical model is developed, and two- and three-dimensional transient and steady-state simulations of the liquid metal-driven abrasive flow are conducted. Results demonstrate that this method effectively removes material from the inner walls of straight channels during cyclic motion. Utilizing continuous electrowetting, an experimental apparatus was designed, where gallium‑indium liquid metal propelled silicon carbide abrasives against PMMA channel walls. Experimental results showed effective material removal, consistent with finite element simulations, confirming the feasibility of this innovative approach.

Predictive model and optimization of micromixers geometry using Gaussian process with uncertainty quantification and genetic algorithm

Abstract Microfluidic devices are gaining attention for their small size and ability to handle tiny fluid volumes. Mixing fluids efficiently at this scale, known as micromixing, is crucial. This article builds upon previous research by introducing a novel optimization approach in microfluidics, combining Computational Fluid Dynamics (CFD) with Machine Learning (ML) techniques. Our research focuses on enhancing global optimization techniques while minimizing computational costs. It draws inspiration from a Y-type micromixer, initially featuring cylindrical grooves on the main channel's surface and internal obstructions. Simulations, conducted using OpenFOAM software, evaluate the impact of circular obstructions on mixing percentage and pressure drop, considering variations in obstruction diameter and offset. A Gaussian Process (GP) was utilized to model the data, providing model uncertainty. This study optimizes geometries by using genetic algorithm (GA) based on the reduced order model provided by GP. Results align with previous research, showing that medium-sized obstructions (137 mm diameter, 10 mm offset) near the channel wall are optimal. This approach not only provides efficient microfluidic optimization with uncertainty quantification but also highlights the effectiveness of combining CFD and ML techniques in achieving desired outcomes.

Seismic geomorphology and reservoir conditions of a Middle Miocene submarine channel system in the Taranaki basin, New Zealand

Deepwater channels function as vital deep-sea hydrocarbon reservoirs and as major routes for moving terrestrial clastic sediment to deepwater environments. A high-resolution sequence stratigraphic framework was built for the deepwater area of the Taranaki Basin using high-resolution three-dimensional (3D) seismic data, and various seismic interpretation techniques, including seismic attribute analysis, were applied. The principal controlling factors and petroleum development potential of the Middle-Miocene channel system were investigated with sequence stratigraphy and seismic geomorphology. Four understandings were primarily attained in this study: (1) depending on the different levels of the channel surfaces, the channel system can be divided into five sedimentary units (SU1-SU5), which correspond to the five stages of channel system evolution. These surfaces include one primary draping surface (PDS), five secondary channel erosion surfaces (SCES), and several tertiary channel erosion surfaces (TCES). (2) with the use of seismic facies analysis, six sedimentary elements were identified in the channel system: pelagic deposits (PDs), mass transport deposits (MTDs), outer levee complex (OLC), inner levee and terrace complex (ILTC), and turbidite channel complexes (TCCs). (3) The sedimentary evolution of the channel system was jointly influenced by multiple factors. The sediment supply and submarine geomorphology can directly affect the internal stacking and migration patterns of the channel. In contrast, tectonic activity and relative sea level fluctuations can indirectly affect the sedimentary characteristics of the channel by regulating the components and scale of clastic sediment. (4) SU1, SU2, and SU3 are primarily filled with coarse-grained sediments, which can serve as high-quality hydrocarbon reservoirs. In contrast, SU4 and SU5 can serve as regional cap rocks because they are filled with fine-grained sediments, and the overall channel system can represent a potential hydrocarbon reservoir-cap combination, which can be viewed as a significant research target for upcoming deepwater exploration. Clarifying the sedimentary properties and primary controlling factors at the various evolutionary stages of deepwater channels is vital for predicting the hydrocarbon development potential of the basin and reducing the drilling risk. This also helps with the development of deepwater basins with similar sedimentary environments in New Zealand and elsewhere in the world.

Intercalation of Polyacrylonitrile Nanoparticles in Ti3C2Tx MXene Layers for Improved Supercapacitance.

We report the intercalation of polyacrylonitrile nanoparticles in Ti3C2Tx MXene layers through simple sonication. The use of polyacrylonitrile, which was synthesized via radical polymerization, offered dual benefits: (1) It increased the interlayer spacing of MXene, thereby exposing more surface area and enhancing ion transport channels during charge and discharge cycles, and (2) Integrating MXene with polyacrylonitrile enables the creation of a composite with conductive properties, following percolation principle. X-ray diffraction analysis showed an increase in the c-lattice parameter, indicative of the interlayer spacing, from 22.31 Å for the pristine MXene to 37.73 Å for the MXene-polyacrylonitrile composite. The intercalated polyacrylonitrile nanoparticles facilitated the delamination by weakening the interlayer interactions, especially during sonication. Electrochemical assessments revealed significant improvement in the properties of the MXene-polyacrylonitrile composite compared to the pristine MXene. The assembled asymmetric device achieved a good specific capacitance of 32.1 F/g, an energy density of 11.42 W h/kg, and 82.2% capacitance retention after 10,000 cycles, highlighting the practical potential of the MXene-polyacrylonitrile composite.

Nanometer-thick TiO2 channel thin film transistors as radical monitors for plasma enhanced atomic layer deposition

Nanometer-thick-TiO2-channel thin-film transistors (TFTs) are examined as oxidizing-agent monitors for room-temperature atomic layer deposition (RTALD). RTALD is a plasma-based process using plasma-excited humidified argon where OH radicals oxidize the precursor-gas adsorbed surface. In the TFT, the anatase TiO2 channel, with a thickness of 16 nm, is attached to a 300 nm thick gate capacitor of SiO2, while the channel surface is exposed to the ALD ambient. A heavily doped n-type Si substrate attached to the gate SiO2 is used as the gate electrode. The gate width and length are 1000 and 60 μm, respectively. When the TFT is installed in the RTALD chamber, the drain-current waveform is recorded in the course of the metal organic gas adsorption, evacuation of the residual gas, oxidization, and evacuation. In the present study, three kinds of metal organic (MO) precursors, tetrakis(dimethyl)amino titanium, tris(dimethyl)amino silane, and trimethyl aluminum are examined. The drain current exhibits strong responses upon the exposure of the plasma excited humidified argon. This suggests that OH radicals in the plasma might oxidize the adsorbed MO precursors to produce the OH moieties, where the surface polarization of OH moieties might enhance channel conductivity. The experimental results suggest the applicability of the present TFT as a plasma monitor in RTALD.

Cilia‐Inspired Functional Channels for High‐Speed and Directional PEMFC Drainage

AbstractProton Exchange Membrane Fuel Cells (PEMFC) consist of channels that require efficient drainage for optimum performance. However, it remains a grand challenge to achieve both directed and high‐speed active drainage in PEMFC channels. This greatly limits current PEMFC performance. Herein, inspired by respiratory cilia, a bioinspired structural design strategy is introduced into the channel surface to significantly enhance its active droplet transport efficiency. Two artificial cilia arrays are fabricated and named as plane‐bottom artificial cilia array (PACA) and concave‐bottom artificial cilia array (CACA) according to their respective shapes. PACA demonstrates stable directional transport. The droplet speed reaches as high as 86 mm s−1 with droplet volumes ranging from 10 to 20 µL. This is surpassed by CACA. Its speed reaches as high as 163 mm s−1 for droplet volumes ranging from 10 to 50 µL. PEMFC experimental evaluation of diameter sizes shows that CACA can be tuned for enhancing its electrochemical performance. CACA‐8 achieves the maximum power density (0.5339 W cm−2) at 1.1864 A cm−2, representing an 18.70% increase compared to conventional PEMFC channels. This work provides a promising strategy for the stable and efficient transport of liquid water in PEMFC.

Characterization of rapid tooling with varying inner cooling channel surface roughness

Characterization of rapid tooling with varying inner cooling channel surface roughness

Photoresponse enhanced CsPbBr3 quantum dots quantum-confined in mesoporous PCN-600 single crystal microwires

In this work, the CsPbBr3 quantum dots (QDs) are encapsulated into the mesoporous iron-based metal-organic framework (PCN-600) by using a two-step solvothermal method. The success formation of CsPbBr3@PCN-600 composite is confirmed via SEM, TEM, XRD, FTIR, EDS and other measurements. Besides, the characterization of fluorescence lifetime of CsPbBr3@PCN-600 composite reveals the presence of the electron transfer between PCN-600 and CsPbBr3 QDs. Especially, CsPbBr3@PCN-600 exhibits a prominent emission peak at 473 nm due to the quantum confinement effect, and the photoluminescence quantum yield of CsPbBr3 QDs protected by the mesoporous PCN-600 increases to 71% compared to 52% of the pristine CsPbBr3 QDs. Also, the protection of CsPbBr3 QDs by the PCN-600 channel enhances the luminescence stability, thermal stability and blue-light stability of CsPbBr3. In fact, under light illumination, the photogenerated carriers from the encapsulated CsPbBr3 QDs could be captured by catalytically active sites on the inner surface of the PCN-600 channel. This charge capture effect can increase the photocurrent and implies much effective separation of electron-hole pairs of the CsPbBr3@PCN-600 composite. These results make this composite a promising candidate for high-performance photoelectronic devices.

Democratizing Access to Microfluidics: Rapid Prototyping of Open Microchannels with Low-Cost LCD 3D Printers.

Microfluidics offer user-friendly liquid handling for a range of biochemical applications. 3D printing microfluidics is rapid and cost-effective compared to conventional cleanroom fabrication. Typically, microfluidics are 3D printed using digital light projection (DLP) stereolithography (SLA), but many models in use are expensive (≥$10,000 USD), limiting widespread use. Recent liquid crystal display (LCD) technology advancements have provided inexpensive (<$500 USD) SLA 3D printers with sufficient pixel resolution for microfluidic applications. However, there are only a few demonstrations of microfluidic fabrication, limited validation of print fidelity, and no direct comparisons between LCD and DLP printers. We compared a 40 μm pixel DLP printer (∼$18,000 USD) with a 34.4 μm pixel LCD printer (<$380 USD). Consistent with prior work, we observed linear trends between designed and measured channel widths ≥4 pixels on both printers, so we calculated accuracy above this size threshold. Using a standard IPA-wash resin and optimized parameters for each printer, the average error between designed and measured widths was 2.11 ± 1.26% with the DLP printer and 15.4 ± 2.57% with the 34.4 μm LCD printer. Printing with optimized conditions for a low-cost water-wash resin designed for LCD-SLA printers resulted in an average error of 2.53 ± 0.94% with the 34.4 μm LCD printer and 5.35 ± 4.49% with a 22 μm LCD printer. We characterized additional parameters including surface roughness, channel perpendicularity, and light intensity uniformity, and as an application of LCD-printed devices, we demonstrated consistent flow rates in capillaric circuits for self-regulated and self-powered delivery of multiple liquids. LCD printers are an inexpensive alternative for fabricating microfluidics, with minimal differences in fidelity and accuracy compared with a 40X more expensive DLP printer.

The Effect of Channel Surface Roughness on Two–Phase Flow Patterns: A Review

This review article highlights the critical impact of surface roughness in modifying the structure of two-phase flow within mini- and microchannels, particularly in processes such as boiling and condensation. Channel surface roughness enhances flow resistance, affects the distribution of vapor bubbles, and enhances heat transfer by providing additional nucleation sites. Several experiments have shown that while increased surface roughness enhances the efficiency of heat transfer, increased flow resistance may hurt system performance. This is so because too high a surface roughness negatively impacts flow resistance, a factor of importance in the optimization for a balance between heat transfer and flow resistance, especially in high-performance compact heat exchangers. Furthermore, the review identifies that higher-degree measurement and characterization techniques of the surface roughness are increasingly required, as traditional 2D parameters may not fully represent the actual physics of complex surface interactions in two-phase flow systems. Consequently, the article calls for further research that can examine the exact relationship between roughness, flow structure, and thermal performance with the aim of improving design strategies for future heat exchanger technologies.

Luminescence Changeable CO2-Storage Cylinder: Triple-Stranded Helical Eu(III)/Tb(III) Fluorinated MOFs with Amide Linkers.

Triple-stranded helical lanthanide MOFs with CO2 adsorption properties were investigated. Lanthanide MOFs ([Eu0.1Tb0.9(hfa)3(dpa)]n) are composed of lanthanide luminophores (Eu(III) and/or Tb(III) ions), fluorinated antenna ligands (hfa: hexafluoroacetylacetonate), and polyamide-type linker ligands (dpa: 4-(diphenylphosphoryl)-N-(4-(diphenylphosphoryl)phenyl)benzamide). The cylindrical structure was characterized by single-crystal X-ray analysis, thermogravimetric analysis, and gas adsorption measurements. The inner surfaces of the cylindrical channels were covered with the fluorine atoms of the hfa ligands. The emission intensity ratio (IEu/ITb) in [Eu0.1Tb0.9(hfa)3(dpa)]n is affected by the CO2 gas adsorption behavior. The change in IEu/ITb value was caused by the intermolecular interactions between the CO2 gas molecules and the fluorinated ligands, resulting in an electronic structural change of the lowest triplet excited state in the photosensitized hfa ligands.

Satellite observations of surface water dynamics and channel migration in the Yellow River since the 1980s

Study regionthe Yellow River (YR) in China. Study focusDue to climate change and human activities, YR channel morphology has undergone significant spatiotemporal variations. Yet, a comprehensive understanding of channel migration in YR and its driving factors remains unclear. Here, we developed a multi-index water extraction method to track the changes in surface water and river channel migration of YR based on Landsat imagery since the 1980s. New hydrological insights for the regionWe find that the average surface water area of YR over the past four decades is 4013 km2, with 73.5 % of permanent surface water. Notably, the surface water extent has experienced a 9 % increase since the 1980s, while the river channel has undergone a 12.2 % decrease. The YR channel’s centerline exhibits diverse change patterns across the entire basin, which can be broadly categorized into six types ranging from unchanged to reverse migration. We identify that climate, particularly temperature and precipitation, contributed 71 % of channel changes in the upper reaches, while 65 % of changes in the lower reaches are from human activities, including reservoir operations and water management policies. Our results unveil the variations in water extent and channel migration of the YR, offering new insights into the interactions between channel migration and climate change and human activities in the YR over the past four decades.

Intergrowth MFI Zeolite with Inverse Al Zoning and Predominant Sinusoidal Channels for Highly Selective Production of Styrene.

ZSM-5 zeolites with accessible micropore architecture and tunable acid-base sites are important shape-selective catalysts. However, the presence of exposed straight channels and the external acid-base sites of conventional ZSM-5 has a negative impact on shape selectivity. Herein, we report on the direct synthesis of an intergrowth ZSM-5 zeolite mimicking the mortise-tenon joints. It can be revealed by various methods that the mortise-tenon ZSM-5 shows an inverse Al gradient from the surface to the core of the zeolite. More importantly, the sinusoidal channels predominantly opened to their external surfaces are constructed. The shape-selective capability of the ZSM-5 zeolite has been fully exploited due to the intrinsic inert external surface and unique sinusoidal channel features, thereby resulting in high styrene selectivity (>90%) and good catalytic stability (>100 h) in the toluene side-chain alkylation reaction. In addition, in situ DRIFTS confirms that this intergrowth ZSM-5 contributes to the formation of more active intermediates of HCOO* and H3CO*, which is another reason responsible for the superior performance.

Nanofluid channels mitigated Zn2+ concentration polarization prolonged over 30 times lifespan for reversible zinc anodes

Despite interfacial engineering protects zinc anode from electrolyte corrosion, the suppressed kinetics process on the anode surface/interface circumscribes their cyclic stability, especially dendritic growth induced by ion concentration gradients. Here, the zinophilic nanofluid channels (ZNC) protective layer on zinc surface are designed for the rapid Zn2+ transport kinetic in the reversible cycling process. The ZNC demonstrates high separation pressure between ions and the channel surface due to the capillary effect, allowing Zn2+ to quickly migrate along the channel wall (Zn2+ transference numbers up to 0.72). Therefore, the unique channel modules alleviate concentration polarization from rapid Zn2+ consumption and maintain uniform deposition of Zn ions. Consequently, The ZNC protective layer anode exhibits significantly improved cycle life by >30 times (over 4000 h at 1 mA cm−2) that of bare Zn. The full battery exhibits stable cycling performance with excellent capacity retention (∼100 %) after 5000 cycles. Our work provides innovative insights into the role of nanofluids in improving the stability of zinc anodes, offering enlightening perspectives for long-cycle life zinc-based batteries.

Facilitating water droplet removal from surfaces using air flow and wettability gradients

A new method is proposed to mitigate ice accretions on wind turbine blades via the creation of a microstructural gradient surface geometry that facilitates spontaneous water droplet motion along the surface. The wettability gradients are formed by laser etching 35 μm wide, 35 μm deep channels into aluminum to form a surface with a gradually increasing solid area fraction. Different design variations are then proposed and systematically evaluated on the merits of their performance. An analytical model is also derived based on a balance of hysteresis and drag forces to predict the critical air speed necessary for droplet movement as a function of the droplet size and surface contact angle. Experimentation has shown good agreement with the model for both the baseline and fixed-pitch channel surfaces and has also demonstrated that, in certain cases, up to 70 % lower critical air speeds are needed to initiate droplet motion on these microstructured surfaces.

Affinity-based 3D-printed microfluidic chip for clinical sepsis detection with CD69, CD64, and CD25

Sepsis is a life-threatening immune response to infection in the body, eventually resulting in fatal organ failure. Current methods utilize blood cultures and quick-Sequential-Organ-Failure-Assessment (qSOFA), but there is a need for more accurate and time-sensitive diagnostic methods to improve survival rates. We present a 3D-printed microfluidic chip that bioconjugates antibodies CD69, CD64, and CD25 to channel surfaces to capture sepsis cells in blood samples and validate it with clinical samples (n = 125 septic, n = 10 healthy). Other variables were taken such as healthy volunteer blood samples and patient demographics to validate and confirm our device’s diagnostic ability. Statistical differences were found between healthy volunteer and sepsis patient antigen cell counts (CD69 p-value < 0.001, CD64 p-value < 0.004, CD25 p-value < 0.0009), and were confirmed using principal component analysis. Demographics such as length of stay, age, culture results, and need for surgery also factored into sepsis detection on a smaller scale than the antigen cell counts. The receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.989, 0.988, and 0.992 for CD69, CD64, and CD25, respectively, and a combined biomarker panel of 0.997. Overall, the device performed within a shorter time frame of 4 h compared to standard blood culture tests and was validated for use in detecting sepsis in patients.

Enhanced Electrical Polarization in van der Waals α-In2Se3 Ferroelectric Semiconductor Field-Effect Transistors by Eliminating Surface Screening Charge.

A van der Waals (vdW) α-In2Se3 ferroelectric semiconductor channel-based field-effect transistor (FeS-FET) has emerged as a next-generation electronic device owing to its versatility in various fields, including neuromorphic computing, nonvolatile memory, and optoelectronics. However, screening charges cause by the imperfect surface morphology of vdW α-In2Se3 inhibiting electrical polarization remain an unresolved issue. In this study, for the first time, a method is elucidated to recover the inherent electric polarization in both in- and out-of-plane directions of the α-In2Se3 channel based on post-exfoliation annealing (PEA) and improve the electrical performance of vdW FeS-FETs. Following PEA, an ultra-thin In2Se3-3xO3x layer formed on the top surface of the α-In2Se3 channel is demonstrated to passivate surface defects and enhance the electrical performance of FeS-FETs. The on/off current ratio of the α-In2Se3 FeS-FET has increased from 5.99 to 1.84 × 106, and the magnitude of ferroelectric resistance switching has increased from 1.20 to 26.01. Moreover, the gate-modulated artificial synaptic operation of the α-In2Se3 FeS-FET is demonstrated and illustrate the significance of the engineered interface in the vdW FeS-FET for its application to multifunctional devices. The proposed α-In2Se3 FeS-FET is expected to provide a significant breakthrough for advanced memory devices and neuromorphic computing.