Miniature System Research Articles

Seamless integration of Internet of Things, miniaturization, and environmental chemical surveillance.

IoT is a game-changer across all fields, including chemistry. Embracing sustainable practices and green chemistry, the miniaturization and automation of systems, and their integration into IoT is key to achieving these principles, as a rising trend with momentum. Particularly, IoT and analytical chemistry are linked in the rapid exchange of analytical data for environmental, industrial, healthcare, and educational applications. Meanwhile, cooperation with other fields of science is evident, and there is a prompt and subjective analysis of information related to analytical systems and methodologies. This paper will review the concepts, requirements, and architecture of IoT and its role in the miniaturization and automation of analytical tools using electronic modules and sensors. The aim is to explore the standards and perspectives of IoT and its interaction with different aspects of analytical chemistry. Additionally, it aimed to explain the basics and applications of IoT for chemists, and its relevance to different subfields of analytical chemistry, particularly in the field of environmental chemical surveillance. The article also covers updating IoT devices and creating DIY-based degradation devices to enhance the educational aspect of chemistry and reduce barriers to lab facilities and equipment. Lastly, it will explore how IoT is really important and how it's going to significantly impact analytical chemistry.

Extended-depth-of-field imaging with an ultra-thin folded lens

Optical systems with extended depth of field (EDOF) are crucial for observation and measurement applications, where achieving compactness and a substantial depth of field (DOF) presents a considerable challenge with conventional optical elements. In this paper, we propose an innovative solution for the miniaturization of EDOF imaging systems by introducing an ultra-thin annular folded lens (AFL). To validate the practical feasibility of the theory, we design an annular four-folded lens with an effective focal length of 80.91 mm and a total thickness of only 8.50 mm. Simulation results show that the proposed folded lens has a DOF of 380.55 m. We further developed an AFL-based test system exhibiting a resolution of 0.11 mrad across a wide wavelength range of 486–656 nm. Additionally, we present experimental results from a miniature compact prototype, which further highlights the promising potential of folded lenses for long-range EDOF imaging.

Loss-Optimized Design of Magnetic Devices.

Maximizing efficiency, power density, and reliability stands as paramount objectives in the advancement of power electronic systems. Notably, the dimensions and losses of magnetic components emerge as primary constraints hindering the miniaturization of such systems. Researchers have increasingly focused on the design of loss minimization and size optimization of magnetic devices. In this paper, with the objective of minimizing the loss of magnetic devices, an optimal design method for the winding structure of devices is proposed based on the coupling relationship between the loss prediction model and the design variables. The method examines the decoupling conditions between the design variables and the loss model, deriving optimized design closure equations for the design variables. This approach furnishes a technical foundation for the miniaturized design of miniature apparatuses incorporating magnetic components, offering a straightforward and adaptable design methodology. The finite element method simulation results and experimental measurement data verify the accuracy of the prediction of the proposed method and the validity of the optimal design theory of device loss.

Miniature Monitoring System for Environmental Indicators and Physiological Signs

Miniature Monitoring System for Environmental Indicators and Physiological Signs

In-situ self-assembly growth of controllable gold nanoparticles film

Because of the strong light absorption and/or scattering, nano scaled gold has many favorable optic and electric properties. With the continuous miniaturization of nano photoelectronic devices and nano electromechanical systems, there is an urgent demand for controllable and tailored gold nanoparticles film with excellent performance. Here, a modified HAuCl4-NaOH-CTAB (cetyltrimethylammonium bromide) aqueous solution system was utilized to self-assembly synthesize gold nanofilm on glass substrates. The high concentration NaOH is not only reducing Au3+ to Au0, but facilitating interfacial assembly of gold nanostructure at liquid–solid interface via etching glass surface. Based on this growth kinetic, the gradient, well-designed and in-situ growing gold nanoparticles film can be achieved on any SiO2 contained substrates by controlling the growth time in the reaction system. Furthermore, the in-situ self-assembled gold nanoparticles film can be act as plasmon substrates for surface-enhanced Raman scattering (SERS) or plasmonic enhanced semiconductor lasing, even gold electrodes.

Random broadband filters based on combination of metasurface and multilayer thin films for hyperspectral imaging

Metasurface based micro-spectrometer presents a promising avenue for achieving compact, lightweight, and cost-effective solutions for miniaturization of hyperspectral imaging systems. Nevertheless, this type of design encounter limitations primarily due to constrained manipulation mechanism of light field, resulting in high cross-correlation among transmission spectra and imperfect reconstructed images. In this paper, we propose and numerically demonstrate a micro-spectrometer based on metasurface combined with multilayer thin films, whose spectral response improves performance for application, i.e. achieving low spectral cross-correlation. Additionally, we incorporate particle swarm optimization with compressed sensing algorithm to optimize the proposed micro-spectrometer. This approach effectively reconstructs both narrowband and broadband hyperspectral signals with minimal error, achieving an impressive 2 nm spectral resolution. The simulation results of hyperspectral imaging demonstrated that the proposed methodology successfully reconstructs broadband hyperspectral images with an average spectral fidelity of 91.42%. This method holds significant potential for integrating into smartphones and other portable spectrometers, advancing the design of compact hyperspectral imaging systems.

Miniaturized design of multi-octave PA using spoof surface plasmon polaritons

Surface Plasmon Polariton (SSPP), which exhibits subwavelength-scaled field confinement, can be realized at microwave frequencies by ultrathin corrugated metallic strips, providing significant potential for circuit and system miniaturization. A number of SSPP units were employed in this study to design input and output matching networks of a multi-octave RF power amplifier (PA) for the purpose of reducing the overall circuit size. The designed SSPP-based PAs were fabricated and demonstrated to have an output power between 39.1 dBm and 41.8 dBm, and a power added efficiency (PAE) ranging between 60.2 % and 69.8 % in the frequency range of 0.8 GHz to 3.1 GHz, with a size of 35.5 mm * 46.7 mm, which achieves a 47 % size reduction compared to the traditional transmission-line based PA. A highly efficient global optimization method, the Bayesian Optimization (BO), was utilized to further enhance performance. SSPP PA's average output power and PAE have been improved by approximately 0.3 dBm and 2.6 %, respectively. Its overall size remains at the same level. With the use of a 20 MHz 5GNR signal, digital pre-distortion (DPD) has been implemented, and the linearity of the PA has been improved.

Simulation of a two-phase loop thermosyphon using a new interface-resolved phase change model

The remarkable progress made in power electronics has been coupled with the miniaturization of systems, requiring high-performance cooling. A solution that has garnered significant interest involves the use of two-phase loops, in which heat transfer is associated with the phase change of the working-fluid. This paper aims at modeling two-phase flow with separated phases in a gravity-driven two-phase loop. The Volume-of-Fluid method is employed to capture the moving interface. Amid the variety of the phase change models available in the literature, we have chosen to employ a hybrid model: a subgrid-scale model to generate phase change at the wall in the absence of an interface, and a interface-resolved model for phase change at pre-existing liquid-vapor interfaces. These models have been implemented in the OpenFOAM computational code. The developed solver makes possible the simulation of compressible laminar two-phase flow with diabatic liquid-vapor phase change. Conjugate heat transfer between the wall and the fluid is also taken into account. Two-dimensional numerical simulations demonstrate that the developed solver is capable of reproducing flow regimes obtained from experiments, including the formation of Taylor bubbles and the propulsion of liquid from the evaporator to the condenser during geyser boiling. Furthermore, this study examines how the filling ratio affects flow regimes and performance.

Viral Delivery of Compact CRISPR-Cas12f for Gene Editing Applications.

Treating human genetic conditions invivo requires efficient delivery of the CRISPR gene editing machinery to the affected cells and organs. The gene editing field has seen clinical advances with ex vivo therapies and with invivo delivery to the liver using lipid nanoparticle technology. Adeno-associated virus (AAV) serotypes have been discovered and engineered to deliver genetic material to nearly every organ in the body. However, the large size of most CRISPR-Cas systems limits packaging into the viral genome and reduces drug development flexibility and manufacturing efficiency. Here, we demonstrate efficient CRISPR gene editing using a miniature CRISPR-Cas12f system with expanded genome targeting packaged into AAV particles. We identified efficient guides for four therapeutic gene targets and encoded the guides and the Cas12f nuclease into a single AAV. We then demonstrate editing in multiple cell lines, patient fibroblasts, and primary hepatocytes. We then screened the cells for off-target editing, demonstrating the safety of the therapeutics. These results represent an important step in applying CRISPR editing to diverse genetic sequences and organs in the body.

State of the art of micro vapour-compression systems

Thermal management is becoming more challenging due to the increasing compactness and computational power of appliances. Affordable and efficient solutions include active liquid cooling methods, thermoelectric cooling, and the use of heat pipes. From these, vapour-compression technologies achieve the highest power density. However, the downscaling of vapour-compression for cooling of personal computers or workstations is rather problematic from several different reasons. The first problem concerns the low second law efficiency of miniature vapour-compression systems. The second problem concerns the available space occupation of such a cooling system. Moreover, miniature and high-power density condensers and evaporators have not yet been adequately researched and developed to date. In this review, we present several vapour-compression refrigeration systems that are based in some way on the miniaturisation of systems or individual components – evaporators, condensers, and compressors. These are presented and compared in terms of cooling power, COP, and the second law efficiency. At the end of the manuscript, guidelines for future improvements and the implementation of miniature vapour-compression systems are presented.

Miniaturization design of laser detection device for naval gun composite fuse

Naval gun weapons are the only weapon system on board that can undertake various combat tasks such as shore fire support, sea attack, air defense and missile defense, and rapid response to emergencies. A new type of naval gun laser-radio composite fuse(naval gun composite fuse) is proposed to address the issue of naval gun fuses being susceptible to interference and failure in a single radio proximity system. This improves the multiple operational effectiveness of naval guns and the adaptability of naval gun ammunition to electromagnetic and other interference environments. In response to the limitation of small size of naval gun fuses, the overall structure and miniaturized laser detection device were designed separately. Firstly, a miniaturized 4-channel narrow pulse high repetition frequency laser detection method with uniform forward circumferential distribution is adopted to achieve compatibility with the original naval gun fuse structure, the simulation results indicate that the structural deformation and strength meet the requirements. Secondly, by designing a laser emission collimating lens that is glued together with a small spherical lens and a small concave cylindrical mirror, the outer envelope size is only Φ5x3mm. The simulation results show that at a distance of 20mm from the laser emission window, the spot diameter is 0.66mm and the divergence angle is 1.9 °, achieving good laser collimation and miniaturization of the emission optical system. Finally, the receiving optical system reduces its volume by adding a receiving objective and a field mirror. The effective aperture of the receiving objective is 10mm, the diameter of the field mirror is 5mm, the focal length is 11.1mm, and the receiving field angle is 5 °. The simulation results show that the laser spot radius on the photosensitive surface of the photodetector is 0.06mm, which meets the requirements of photodetectors.

Experimental investigation on the influence of electronic expansion valve opening on the performance of miniature refrigeration system

In the cooling of personnel and electronic equipment under specific conditions, the miniature refrigeration system needs to provide different cooling capacity to adapt to different working conditions. At present, most scholars use capillaries as throttling components. Compared with capillaries, miniature refrigeration systems using electronic expansion valves as throttling components can provide a wider range of cooling capacity adjustment. Therefore, this study constructed a miniature vapor compression refrigeration system based on electronic expansion valves as throttling devices, with a system weight of 3.0 kg and dimensions of 380 mm × 300 mm × 200 mm. The experiment investigated the impact of electronic expansion valve opening on compressor power, cooling capacity, and COP under different refrigerant charge conditions. Results indicated that at an electronic expansion valve opening of 90, within the experimental range, there was a relative change in cooling capacity of 39.85 % and a relative change in COP of 29.11 % as the refrigerant charge increased. Refrigerant charge had a significant effect on the cooling capacity and COP of the miniature refrigeration system. Under the optimal refrigerant charge of 70 g, within the experimental range, there was a relative change in cooling capacity of 88.14 % with varying electronic expansion valve opening. The use of electronic expansion valves as throttle components in miniature refrigeration systems allows for a wider range of cooling capacity adjustments, making them suitable for more cooling conditions.

Coplanar Waveguide (CPW) Loaded with Symmetric Circular and Polygonal Split-Ring Resonator (SRR) Shapes

This paper investigates the performance of coplanar waveguide (CPW) structures loaded with symmetric circular and polygonal split-ring resonators (SRRs) for microwave and RF applications, leveraging their unique electromagnetic properties. These properties make them suitable for metamaterials, sensors, filters, resonators, antennas, and communication systems. The objectives of this study are to analyze the impact of different SRR shapes on the transmission characteristics of CPWs and to explore their potential for realizing compact and efficient microwave components. The CPW-SRR structures are fabricated on a dielectric substrate, and their transmission properties and spectrogram are experimentally characterized in the frequency range of 4 GHz to 10 GHz with the rotation angles of the SRR gap. The simulation results demonstrate that the resonant frequencies and magnitude of the transmission coefficient of the CPW-SRR structures are influenced by the geometry of the SRR shapes and the rotation angles of the SRR gap, with certain shapes exhibiting enhanced performance characteristics compared to others. Moreover, the symmetric circular and polygonal SRRs offer design flexibility and enable the realization of miniaturized microwave components with improved performance metrics. Overall, this study provides valuable insights into the design and optimization of CPW-based microwave circuits utilizing symmetric SRR shapes, paving the way for advancements in the miniaturization and integration of RF systems.

High-dimensional Poincaré beams generated through cascaded metasurfaces for high-security optical encryption

Optical encryption plays an increasingly important role in the field of information security owing to its parallel processing capability and low power consumption. Employing the ultrathin metasurfaces in optical encryption has promoted the miniaturization and multifunctionality of encryption systems. Nevertheless, with the few number of degrees of freedom (DoFs) multiplexed by single metasurface, both key space and encoding space are limited. To address this issue, we propose a high-security and large-capacity optical encryption scheme based on perfect high-dimensional Poincaré beams with expanded DoFs. By cascading two arrayed metasurfaces, more beam properties can be independently engineered, which gives rise to the extensively expanded key and encoding spaces. Our work provides a promising strategy for optical encryption with high security level and large information capacity and might facilitate the applications of Poincaré beams in optical communications and quantum information.

All-silicon metalens for broadband achromatic polarization multiplexing in long-wave infrared wavelengths

Traditional long-wave infrared polarimetry usually relies on complex optical setups, making it challenging to meet the increasing demand for system miniaturization. To address this problem, we design an all-silicon broadband achromatic polarization-multiplexing metalens (BAPM) operating at the wavelength range of 9–12 µm. A machine-learning-based design method is developed to replace the tedious and computationally intensive simulation of a large number of meta-atoms. The results indicate that the coefficients of variation in focal length of the BAPM are 3.95% and 3.71%, and the average focusing efficiencies are 41.3% and 40.5% under broadband light incidence with x- and y-polarizations, respectively.

Neural‐Optic Co‐Designed Polarization‐Multiplexed Metalens for Compact Computational Spectral Imaging

AbstractIn the expanding fields of mobile technology and augmented reality, there is a growing demand for compact, high‐fidelity spectral imaging systems. Traditional spectral imaging techniques face limitations due to their size and complexity. Diffractive optical elements (DOEs), although helpful in reducing size, primarily modulate the phase of light. Here, an end‐to‐end computational spectral imaging framework based on polarization‐multiplexed metalens is introduced. A distinguishing feature of this approach lies in its capacity to simultaneously modulate orthogonal polarization channels. When harnessed in conjunction with a neural network, it facilitates the attainment of high‐fidelity spectral reconstruction. Importantly, the framework is intrinsically fully differentiable, a feature that permits the joint optimization of both the metalens structure and the parameters governing the neural network. The experimental results presented herein validate the exceptional spatial‐spectral reconstruction performance, underscoring the efficacy of this system in practical, real‐world scenarios. This innovative approach transcends the traditional boundaries separating hardware and software in the realm of computational imaging and holds the promise of substantially propelling the miniaturization of spectral imaging systems.

Using miniature experiments to reveal strength gradients in battery casings

Complex metallic structures are often manufactured through multi-step forming or casting processes that induce severe mechanical property variations within the final part. Instead of using the virgin material properties to predict the final part performance, the local material properties after manufacturing need to be known. A novel comprehensive testing methodology is presented allowing the resolution of spatial gradients in the plasticity and fracture properties in metallic structures. It involves using a recently-developed miniature linear-motion system that probes the material within 2 mm wide gage sections (uniaxial, notched and central hole tension, in-plane shear). Additionally, a novel mini-bulge testing system is presented along with a mini-punch system to provide further insight into the local material response for biaxial loading conditions. A full testing campaign comprising 60 miniature samples is performed on all sides of a prismatic aluminum casing for Li-ion battery cells. The results demonstrate significant property variations with more than 30 % higher yield stresses for the side walls as compared to the bottom section. The miniature specimens allow identifying a location-dependent anisotropy, which would otherwise be missed by standard-sized samples. Furthermore, it is shown that the anisotropic Yld2000 plasticity model and the stress-state dependent Hosford-Coulomb fracture initiation model can be fully identified using results from experiments on miniature specimens only.

Body morphometry did not affect the accuracy of a second-generation, miniature imageless navigation system for total hip arthroplasty (THA) using a posterior approach

IntroductionSome modern imageless navigation platforms for total hip arthroplasty (THA) rely on virtual frontal and sagittal planes determined with the patient in the lateral decubitus position. Body morphometry that changes with gender, body mass index, and other demographic factors may affect accuracy in patient positioning and consequently, navigation accuracy. The objective of this study was to analyze the influence of patient factors on the intraoperative accuracy of a second-generation imageless computer-assisted surgery platform. Methods325 consecutive patients undergoing posterior approach, navigated THA arthroplasty for primary osteoarthritis by a single surgeon were retrospectively reviewed. An optic-based imageless navigation system referenced off a generic sagittal and coronal plane was used to determine acetabular inclination and anteversion. Acetabular accuracy was determined by assessing differences between intraoperative values and those obtained from measuring standardized 6-week follow-up radiographs. The effect of age, gender, BMI, race, ethnicity, and laterality on acetabular accuracy was assessed via t-tests, Pearson correlation and ANOVA. ResultsGender had a significant impact on raw inclination accuracy (females and males had an average error of 1.41° and −1.03°, respectively – p < 0.001). There was a weak correlation between acetabular accuracy and patient age and BMI as a continuous variable (both absolute γ < 0.2). No difference was found between acetabular accuracy and BMI groups. ConclusionThis second-generation imageless computer assisted device provided accurate cup positioning regardless of patient's BMI. Gender was the only factor impacting inclination accuracy.

Advancement in Generation and Application of Microfluidic Chip Technology

Microfluidics is an interdisciplinary topic of research that draws inspiration from other areas such as fluid dynamics, microelectronics, materials science, and physics. Microfluidics has made it possible to create microscale channels and chambers out of a broad variety of materials by borrowing ideas from a number of different fields. This has opened up exciting possibilities for the development of platforms of any size, shape, and geometry using a variety of approaches. One of the most significant advantages of microfluidics is its versatility in applications. Microfluidic chips can be used for a variety of purposes, such as incorporating nanoparticles, encapsulating and delivering drugs, targeting cells, analyzing cells, performing diagnostic tests, and cultivating cells. This adaptability has led to the development of several device-like systems for use in a range of settings. In this study, we explore cutting-edge novel applications for microfluidic and nanofabrication technologies. We examine current developments in the area of microfluidics and highlight their potential for usage in the medical industry. We pay special attention to digital microfluidics, a recently developed and very useful technique for illness diagnosis and monitoring. The originality of microfluidics is found in the fact that it allows for the miniaturization of complex systems and processes, paving the way for the creation of cutting-edge gadgets with wide-ranging practical applications. Microfluidics has the potential to transform various fields, including medicine, biotechnology, environmental monitoring, and more. The development of novel microfluidic platforms, coupled with advancements in digital microfluidics, promises to revolutionize the way we diagnose, treat, and monitor diseases.

A design methodology of miniature photoacoustic cell based on beam energy distribution and acoustic resonator coupling

In photoacoustic spectroscopy, the photoacoustic cell plays the role of amplifying the photoacoustic signal, and the optimization of its parameters affects the sensitivity and dimensions of the whole system. However, none of the current optimization studies of photoacoustic cells have considered in depth the influence of beam waist radius, which limits the reduction of the size of photoacoustic cells. In this paper, based on the theory of photoacoustic spectroscopy, considering the inhomogeneity of the spatial distribution of the Gaussian beam energy and neglecting the loss of the beam in the acoustic resonator, a theoretical model of the effect of the beam waist radius on the cell constant of the first-order longitudinal resonant frequency is established. Six photoacoustic cells with different resonator radii were designed and measured for acetylene at five different beam waist radii. The relationship among beam waist radius, radius of acoustic resonator and cell constants shows that choosing a radius of resonator that matches the waist radius results in a more sensitive and smaller photoacoustic cell. The study provides a reference for the design of miniaturized photoacoustic cells with high sensitivity, thus promising to further improve the miniaturization of photoacoustic spectroscopy systems for more application scenarios.