Precise Fabrication Research Articles

Study and optimization on hyperthermia performance of magnetic fluids modeled by coupled Brownian–Néel rotations

Superparamagnetic nanoparticles (SMNPs) with nonlinear magnetic behavior under alternating magnetic fields hold great potential in biomedical applications, including magnetic hyperthermia, biosensing, magnetic separation, magnetic particle imaging, etc. Magnetic hyperthermia therapy, based on the relaxation movement of SMNPs subjected to an alternating magnetic field, is a promising modality for tumor treatment. Herein, we applied the stochastic Langevin equation to study the magnetic hyperthermia performance of SMNPs by taking the coupled Brownian–Néel rotations into account. The specific absorption rate (SAR) of magnetic fluids is used as a parameter for optimizing the amplitude and frequency of alternating magnetic fields and guiding the design of SMNPs. Specifically, by accounting for the dipole–dipole interactions between SMNPs, it is revealed that these interactions significantly suppress the relaxation behavior of particles, thereby reducing SAR. Furthermore, this study systematically examines the effects of key factors such as particle concentration, particle size, and magnetic anisotropy constant on SAR. The accurate prediction of the rotational and magnetic dynamics of SMNPs under an oscillating magnetic field provides valuable theoretical insights and technical support for the optimized design of external magnetic field systems and the precise fabrication of SMNPs.

Incompatible Geometry Regulation of Nanowire Assemblies Enabled Light-Driven Shape Morphing and Motions.

Photoresponsive shape-changing materials have significant applications in miniaturized smart robotics and biomedicine powered in a remote and wireless manner. Existing light-fuelled soft materials suffer from limited continuous shape manipulation and constrained mobility and locomotive modes. One promising solution is developing a hierarchical structure design approach to integrate rapid, reversible photoactive molecular alignment and mechanically incompatible geometry in a macroscopic system. Here, a nanowire assemblies-induced geometry engineering method is reported for the fabrication of silver nanowire-incorporated nematic liquid crystalline elastomers with prominent anisotropic structures at multi-length scales and incompatible elasticity that show sharp morphological transitions among the rings, helicoids, and spirals with diverse helical configurations. The engineered composite films can realize complex light-driven motions including rotating, rolling, and jumping with the controlled directionality and magnitude that are pre-encoded in their both molecular and macroscopic configurations. Owing to the great controllability of multimodal locomotion, a spiral robot can undertake task-specific configuration to climb up complex terrains. The complete regulatory relationship among molecular orientation, shape geometry, and light-driven motions is also established. This study may open an avenue for elaborate design and precise fabrication of novel shape-morphing materials for future applications in intelligent robotic systems.

A Low-Cost, High-Resolution Thermoplastic Microfluidic Probe for Mass Spectrometry Imaging of Biological Tissue Samples.

Mass spectrometry imaging (MSI) using nanospray desorption electrospray ionization (nano-DESI) has been extensively used for label-free mapping of hundreds of molecules in biological samples with minimal sample pretreatment. While both nano-DESI probes made of two fused silica capillaries and glass microfluidic probes (MFP) have been developed for imaging biological tissues with high spatial resolution, MFPs significantly enhance the robustness and throughput of nano-DESI MSI experiments. Despite their advantages, the fabrication of glass microfluidic devices is costly and requires specialized equipment or cleanroom facilities. Meanwhile, plastic microfluidic devices often suffer from limited solvent compatibility and low fabrication precision, restricting their achievable spatial resolution. To overcome these limitations, we have developed a low-cost microfluidic probe made from cyclic olefin copolymer (COC), a widely used thermoplastic material known for its excellent chemical resistance. The probe is fabricated using wire imprinting and thermal bonding in a standard laboratory setting. We estimate the achievable spatial resolution of the COC-MFP of 5-7 μm and demonstrate its robustness by imaging a large (20.0 mm × 9.5 mm) human kidney tissue section with high sensitivity. This affordable thermoplastic probe makes high spatial resolution nano-DESI MSI more accessible, broadening its applications in the scientific community.

The Optimization of Rotary Bending Die Process: Criteria for the Metal Sheet Angles and Springback Effects

Rotary die bending enables the precise fabrication of sheet metal components across various bending angles, offering high dimensional accuracy, structural stability, and reduced springback. This study employs explicit and implicit numerical simulations using the Abaqus software to analyze the rotary die bending process and springback behavior of SUS304 stainless steel sheets. Five key criteria are investigated: desired angle post-springback (asi), springback factor (ksi), forming stress (Von Mises) at the required bending angle (Sr), residual stress (Von Mises) after springback (Sb), and equivalent plastic strain (PEEQ). These criteria enable accurate predictions of material behavior during rotary die bending, including elastic-plastic deformation and stress distribution. The insights gained support a more flexible design process, enhance the precision of sheet metal bending, and ensure that the final product meets the specified requirements. This research serves as a valuable reference for professionals working with sheet metal components made from various metals and bimetal sheets. Additionally, it informs strategies to mitigate or eliminate residual stress in bent parts, improving reliability and manufacturability.

Error analysis and spectral reconstruction of an infrared static miniature interferometric spectrometer.

Scientific-grade spectrometers with high hyperspectral resolution and high spectral accuracy are desirable in miniaturized optical systems to maintain stable and real-time spectral sampling. Fourier transform spectrometers that utilize high-precision moving mirrors generally struggle to enhance their miniaturization and stable real-time performance. A static infrared spectral measurement method is proposed that uses micro/nano-optical devices as the core of static interference and lightweight imaging. The use of micro/nano step mirrors allows for the instantaneous sampling of spectra. By employing an array of micro/nano lenses, interference imaging for each spectral channel can be accomplished. The spectrometer's all-static micro/nano-optical structure results in a reduction in volume and weight of more than half. Enhanced precision in design and fabrication is achieved through optical error analysis via a full-linkage optical field transmission model. An image edge detection-assisted spectral inversion algorithm is proposed, and the sampling stability and reconstruction accuracy are verified. The repeatability accuracy of interference intensity sampling surpasses 2%, and the peak accuracy of the reconstructed spectrum exceeds the resolution.

Single-Step Production of Doubly Re-entrant Microstructures Through Reaction-Diffusion Photolithography for Omniphobic Surfaces.

Omniphobic surfaces, which repel virtually any liquid regardless of its wettability, have been developed using doubly re-entrant microstructures. Although various microfabrication techniques have been explored, these often require multiple complex steps. In this study, reaction-diffusion photolithography (RDP) is used to fabricate micropost arrays with doubly re-entrant geometries through a single-step ultraviolet (UV) exposure process. To create a doubly re-entrant structure consisting of a central, elongated micropost topped with a short ridge, a photomask featuring a circular window surrounded by a narrow ring-shaped window is employed. This configuration is utilized in the RDP process, which relies on radical polymerization. Vertical growth of the structure from the photomask is achieved by introducing strong UV attenuation along the vertical axis, enabled by increasing the photoinitiator concentration. Concurrently, the growth of the ridge is slowed down by designing the ring window with minimal dimensions. This promotes rapid oxygen diffusion into the ring region, where the radicals generated by UV exposure are consumed through reactions with oxygen, thereby delaying the polymerization. This approach enables precise fabrication of full-length central microposts with short ridges in a single step. The resulting doubly re-entrant structures show high contact angles across various liquids and exhibit robust omniphobic performance.

Low-loss on-chip superconducting microwave circulator assisted by shunting capacitors

Ferrite-free circulators that are passive and readily integratable on a chip are highly sought-after in quantum technologies based on superconducting circuits. In our previous work, we implemented such a circulator using a three-Josephson-junction loop that exhibited unambiguous nonreciprocity and signal circulation, but required junction energies to be within 1% of design values. This tolerance is tighter than standard junction fabrication methods provide, so we propose and demonstrate a design improvement that relaxes the required junction fabrication precision, allowing for higher device performance and fabrication yield. Specifically, we introduce large direct capacitive couplings between the waveguides, which based on the modeling we describe here, requires less stringent junction fabrication tolerance. We implement the design, and measure enhanced “circulation fidelity” above 97%, with optimized on-resonance insertion loss of 0.2 dB, isolation of 18 dB, and power reflectance of −15dB, in good agreement with model calculations. Published by the American Physical Society 2025

Precise Fabrication of Elongated Janus Microparticles

Precise Fabrication of Elongated Janus Microparticles

Investigation of Chip Morphology in Elliptical Vibration Micro-Turning of Silk Fibroin.

Silk fibroin, known for its biocompatibility and biodegradability, holds significant promise for biomedical applications, particularly in drug delivery systems. The precise fabrication of silk fibroin particles, specifically those ranging from tens of nanometres to hundreds of microns, is critical for these uses. This study introduces elliptical vibration micro-turning as a method for producing silk fibroin particles in the form of cutting chips to serve as carriers for drug delivery systems. A hybrid finite element and smoothed particle hydrodynamics (FE-SPH) model was used to investigate how vibration parameters, such as frequency and amplitude, influence chip formation and morphology. This research is essential for determining the size and shape of silk fibroin particles, which are crucial for their effectiveness in drug delivery systems. The results demonstrate the superior capability of elliptical vibration micro-turning for producing shorter, spiral-shaped chips in the size range of tens of microns, in contrast to the long, continuous chips with zig-zag folds and segmented edges generated by conventional micro-turning. The unique zig-zag shapes result from the interplay between the high flexibility and hierarchical structure of silk fibroin and the controlled cutting environment provided by the diamond tool. Additionally, higher vibration frequencies and lower vertical amplitudes promote chip curling, facilitate breakage, and improve chip control, while reducing cutting forces. Experimental trials further validate the accuracy of the hybrid model. This study represents a significant advancement in the processing of silk fibroin film, offering a complementary approach to fabricating short, spiral-shaped silk fibroin particles with a high surface-area-to-volume ratio compared to traditional spheroids, which holds great potential for enhancing drug-loading efficiency in high-precision drug delivery systems.

Atomically Precise Fabrication of Ultranarrow Zigzag CuTe Nanoribbons via Dimensional Regulation.

Artificial dimension control has been playing a vital role in electronic structure manipulation and properties generation. However, systematic investigations into the dimensional regulation, such as transformation from two-dimensional (2D) materials to well-controlled one-dimensional (1D) ribbons, remain insufficient via molecular beam epitaxy. Here, high-quality ultranarrow zigzag CuTe nanoribbons are atomically precisely prepared via the dimensional regulation induced by adjusting the Te chemical potential, utilizing CuSe monolayer as the starting 2D template. Introducing Te atoms into the CuSe monolayer and subsequent annealing, Te atoms replace Se atoms within CuSe lattice. As the Te substitution ratio increases, strain accumulates and elongated nanopores emerge, which expand and interconnect to form 1D CuSe1-xTex (0 ≤ x ≤ 1) nanoribbons and ultimately coalesce into a 1D ultranarrow zigzag CuTe nanoribbons with a honeycomb lattice. The entire structural transformation is verified through scanning tunneling microscopy (STM) and density functional theory (DFT). Contrary to the 2D semiconducting nature of CuSe and CuSe1-xTex monolayers, newly formed 1D CuTe nanoribbons exhibit metallic properties. Intriguingly, DFT calculations further reveal spin-polarized states at the zigzag edges of CuTe nanoribbons. Our proposed dimensional regulation strategy from 2D materials to well-controlled 1D nanoribbons presents avenues for refining and enhancing the synthesis process.

Engineering of hierarchical nano‐convex polymer lattice SERS platforms by template replica‐assisted nanoimprinting

AbstractThe precise fabrication of arrays of gold and silver nanodots (Au&Ag_NDs) to create plasmonic lattices on different substrates through cost‐effective, scalable approaches remains challenging. The aim of this research is to engineer a new class of hierarchical plasmonic lattices based on Au&Ag_NDs generated on polymer substrates via template replica‐assisted nanoimprinting. This method harnesses a combination of nanopatterning via anodization, magnetron sputtering, and annealing to generate Au&Ag_NDs hierarchical plasmonic lattices with tunable features at the nanoscale. These plasmonic lattices are explored as ultrasensitive surface‐enhanced Raman scattering (SERS) platforms for the detection of a model organic (rhodamine B [RhB]). These reproducible model platforms achieve remarkable enhancement to detect RhB molecules, with a low limit of detection of 10−8 M. The enhancement field factor of 107 indicates that the developed plasmonic lattices are adequate for efficient and highly sensitive SERS detection.

Design of transversal piezoelectric boundary acoustic wave filter for inverter drive circuit

Abstract To enhance isolation in gate-drive circuits for multilevel inverters, we proposed transversal piezoelectric boundary acoustic wave (PBAW) filters to replace previously used surface acoustic wave filters. First, we investigated transversal PBAW in a simple and easy-to-fabricate SiO2/Au/LiNbO3 structure. Calculations demonstrated that reducing the number of electrode pairs enhances propagation characteristics; however, this structure does not effectively mitigate signal degradation. Therefore, we investigated the SiO2/Ta2O5/Au/LiNbO3 structure, enabling better PBAW propagation. By optimizing with impedance matching, we achieved an insertion loss of less than 3 dB. To validate the feasibility of a transversal PBAW filter, we also experimentally investigated the SiO2/Au/LiNbO3 structured PBAW filter. Using substrate cut angles and processes available within our research group, we fabricated and evaluated the prototype, confirming PBAW propagation. These results suggest that transversal PBAW filters exhibiting excellent propagation characteristics using SiO2/Ta2O5/Au/LiNbO3 can be achieved with a precise Ta2O5 fabrication process. The study offers a viable solution for enhancing isolation performance in gate-drive circuits.

Dimerizing DNA-AgNCs via a C-Ag+-C structure for fluorescence sensing with dual-output signals.

The unique insertion capability of Ag+ into cytosine-cytosine (C-Ag+-C) mismatch-base pairs enables precise fabrication of DNA-trapped silver nanoclusters (DNA-AgNCs) through varying the DNA sequences, thereby offering precise assembly of DNA-AgNCs and demonstrating great fluorescence applications. However, most of the DNA-AgNC-based fluorescence sensors have a single output signal. Herein, we developed a dimerized DNA-AgNC system through C-Ag+-C connection at the 3'-end of a designed DNA. The formation and crack-up of C-Ag+-C endows DNA-AgNCs with the ability to identify Ag+ and cysteine (Cys) with dual-output signals, changed fluorescence intensity (FI) and wavelength-shift in NIR emission around 815 nm via photoinduced electron transfer (PET), respectively. Superior linearity of FI for Cys and Ag+ concentrations was demonstrated. Meanwhile, the practical utility of this platform was also successfully verified in milk and lake water.

A wide-spectrum mid-infrared electro-optic intensity modulator employing a two-point coupled lithium niobate racetrack resonator

Optical intensity modulators (OIMs) are essential for mid-infrared (mid-IR) photonics, enabling applications such as bond-selective molecular sensing, and free-space communications via atmospheric windows. Integrated photonics offers a compact and cost-effective solution, yet on-chip mid-IR OIMs significantly underperform compared to their near-IR counterparts. Furthermore, despite the potential benefits for system reconfiguration in accessing various communication frequencies and molecular absorption bands, developing a single OIM capable of operating across a broad spectral range remains a challenge. In this study, we introduce an on-chip OIM that operates over a wide wavelength range in the mid-IR, implemented using a racetrack resonator structure in thin film lithium niobate (TFLN). The modulator employs a two-point coupling scheme, allowing active control of the coupling strength to maintain critical coupling and thereby ensuring high modulation extinction across a wide spectral region. This approach not only achieves high modulation performance but also relaxes the design constraints and fabrication precision typically associated with resonator-based modulators, as confirmed through an analytic model. Implemented in TFLN having a wide transmission spectrum and strong electro-optic coefficient, the OIM demonstrates a modulation extinction ratio exceeding 20 dB with an electro-optic efficiency of 7.7 V cm over the wavelength range of 3.3–3.8 μm, which falls within the first atmospheric transmission widow in the mid-IR. This approach can be adapted to other spectral regions, providing a versatile solution for diverse photonic applications.

Exploring Architectural Units Through Robotic 3D Concrete Printing of Space-Filling Geometries

The integration of 3D concrete printing (3DCP) into architectural design and production offers a solution to challenges in the construction industry. This technology presents benefits such as mass customization, waste reduction, and support for complex designs. However, its adoption in construction faces various limitations, including technical, logistical, and legal barriers. This study provides insights relevant to architecture, engineering, and construction practices, guiding future developments in the field. The methodology involves fabricating closed architectural units using 3DCP, emphasizing space-filling geometries and ensuring structural strength. Across three production trials, iterative improvements were made, revealing challenges and insights into design optimization and fabrication techniques. Prioritizing controlled filling of the unit’s internal volume ensures portability and ease of assembly. Leveraging 3D robotic concrete printing technology enables precise fabrication of closed units with controlled voids, enhancing speed and accuracy in production. Experimentation with varying unit sizes and internal support mechanisms, such as sand infill and central supports, enhances performance and viability, addressing geometric capabilities and fabrication efficiency. Among these strategies, sand filling has emerged as an effective solution for internal support as it reduces unit weight, simplifies fabrication, and maintains structural integrity. This approach highlights the potential of lightweight and adaptable modular constructions in the use of 3DCP technologies for architectural applications.

“Grafting to” Rubber Composite for Elastic Dielectric Material

AbstractIn addition to traditional rubber applications, 1,4‐cis‐polyisoprene (cis‐PI) has been utilized in wearable electronics. While synthetic PI typically exhibits lower durability compared to natural rubber (NR), high‐molecular‐weight cis‐PI compensates by offering improved mechanical properties and chemical resistance. The group proposes using a commercial cis‐PI with high molecular weight of 250 000 g mol−1 (PI250K‐C) grafted onto modified nanoparticle structures including silicon dioxide (mSiO2), rutile titanium dioxide (mRTiO2), and anatase titanium dioxide (mATiO2) as an insulator in organic field effect transistors (OFETs) due to its naturally low dielectric constant. The nanoparticles are pretreated with a coupling agent to improve adhesion and prevent aggregation. Rubber composite films, designated X%‐mY‐PI250K‐C (where X = 10, 20, 30% and Y = mSiO2, mRTiO2, mATiO2), are fabricated using sulfur vulcanization. The modified films demonstrate excellent mechanical stress (1.15 ± 0.1 MPa) and elasticity, enduring 50 loading–unloading cycles without residual strain. In contrast, rubber composites produced from simple blending show half the mechanical stress at 0.7 ± 0.3 MPa, which is attributed to nanoparticle agglomeration observed in SEM and EDX results. Additionally, mRTiO2 nanoparticles significantly increase the dielectric constant of PI250K‐C from 2.12 to 12.93, enhancing electrical performance for TFT applications. This study underscores the effectiveness of the “grafting to” approach for producing robust rubber composites, highlighting the importance of nanoparticle selection and fabrication precision for stretchable organic electronics.

A Study on the Development of Real-Time Chamber Contamination Diagnosis Sensors.

Plasma processes are critical for achieving precise device fabrication in semiconductor manufacturing. However, polymer accumulation during processes like plasma etching can cause chamber contamination, adversely affecting plasma characteristics and process stability. This study focused on developing a real-time sensor system for diagnosing chamber contamination by quantitatively monitoring polymer accumulation. A quartz crystal sensor integrated with flexible printed circuit boards was designed to measure the frequency shifts corresponding to polymer thickness changes. An impedance probe was also employed to monitor variations in the plasma discharge characteristics. The sensor demonstrated high reliability with a measurement scatter of 2.5% despite repeated plasma exposure. The experimental results revealed that polymer accumulation significantly influenced the plasma impedance, and this correlation was validated through real-time monitoring and scanning electron microscopy (SEM). The study further showed that the sensor could detect the transition point of the plasma state changes under varying process gas conditions, enabling the early detection of potential process anomalies. These findings suggest that the developed sensor system can be crucial for diagnosing plasma and chamber conditions, providing valuable data for optimizing preventive maintenance schedules. This advancement offers a pathway for improving process reliability and extending the operational lifetime of semiconductor manufacturing equipment.

Silica Waveguide Thermo-Optic Mode Switch with Bimodal S-Bend.

A silica waveguide thermo-optic mode switch with small radius bimodal S-bends is demonstrated in this study. The cascaded multimode interference coupler is adopted to implement the E11 and E21 mode selective output. The beam propagation method is used in design optimization. Standard CMOS processing of ultraviolet photolithography, chemical vapor deposition, and plasma etching are adopted in fabrication. Detailed characterizations on the prepared switch are performed to confirm the precise fabrication. The measurement results show that within the wavelength range from 1530 to 1575 nm, for the E11 mode input, the switch exhibits an extinction ratio of ≥13.1 dB and a crosstalk ≤-22.8 dB at an electrical driving power of 284.8 mW, while for the E21 mode input, the extinction ratio is ≥15.5 dB and the crosstalk is ≤-18.1 dB at an electrical driving power of 282.4 mW. These results prove the feasibility of multimode S-bends in mode switching. The favorable performance of the demonstrated switch promises good potential for on-chip mode routing.

A Comparative Analysis of the Accuracy of Crown Fabricated from Conventional Wax Patterns and CAD/CAM Technology – Milling and 3D Printing

ABSTRACT Background: Digital manufacturing techniques such as milling (subtractive) and 3D printing (additive) are increasingly used in dental restorations. These technologies promise enhanced precision and efficiency compared to traditional methods. However, the accuracy of marginal and internal fits of crowns produced by these techniques remains under-explored. Objective: To evaluate and compare the marginal and internal fit of dental crowns fabricated using two digital manufacturing techniques: Milling (subtractive) and 3D printing (additive). Materials and Methods: A maxillary first molar was replicated to create seven representative dies for each technique. Crowns were fabricated using both milling and 3D printing methods. The fit of the crowns was assessed using the silicone replica technique, measuring occlusal, axial, marginal gaps, and internal fit. Results: 3D printing demonstrated the most precise fit across all measurement points, with significantly smaller discrepancies compared to milling. The two-way ANOVA analysis confirmed a significant effect of the fabrication method on marginal and internal gaps, highlighting the superior performance of 3D printing. However, the silicone replica technique revealed fewer significant differences between the two methods. Conclusion: 3D printing offers enhanced precision and consistency in crown fabrication compared to milling. Despite promising results, further research is necessary to confirm the long-term efficacy and cost-effectiveness of these techniques. Future studies should focus on larger clinical cohorts to validate these findings.

Oxidation Triggered Supramolecular Chirality.

Topochemical reactions normally occurring in the solid and crystalline state exhibit solvent-free and catalyst-free properties, with high atom economy properties, which have been widely applied in materials science and polymer synthesis. Herein, we explore the potential of topochemical reactions for controlling the emergence of supramolecular chirality and the precise fabrication of chiroptical materials. Boronic acid pinacol esters (BPin) were conjugated to naphthalimides containing an inherent chiral cholesteryl group linked by alkyl or benzene spacers. The BPin segments were oxidized by H2O2 to form hydroxyl groups, which enhanced luminescence, reduced steric effects, and increased amphiphilicity. The inherent liposomal aggregates underwent in situ oxidation and transformed into 1D nanoarchitectures, exhibiting macroscopic chirality, active Cotton effects, and circularly polarized luminescence. Oxidation could also initiate an intimate interplay between the building units and the guest molecule, by which the chirality and chiroptical evolution in the multiple component chiral assembly system were realized.