Cavity Surface Research Articles

Duffing Nonlinearity‐Enhanced Optomechanical Mass Sensor

AbstractMeasuring the mass of small molecules is crucial across various fields, and the cavity optomechanical system is a promising candidate for mass sensing due to the direct relationship between the oscillator's resonant frequency and the mass of the sample deposited on the cavity's surface. Previous research has shown that enhancing the effective frequency of the resonator can significantly improve the performance of mass sensors. In this study, the influence of the Duffing nonlinear term is investigated on the cavity optomechanical mass sensing. These computational and numerical simulation results demonstrate that increasing the strength of the Duffing nonlinear term effectively raises the resonator's effective frequency and directly boosts the performance of the mass sensor. These include enhancing detection resolution, reducing measurement errors, and expanding the effective measurement range of mass, which may have applications in fields such as biochemical sensing and environmental monitoring.

Three-dimensional analysis of natural healing of mandibular bone cavities after cyst enucleation.

This cross-sectional study aimed to assess the natural bone healing process in mandibular cystic cavities after enucleation surgery using three-dimensional (3D) analysis. By assessing key indicators, including bone cavity healing percentage, mean reduction in bone cavity radius, and mean bone volume increase, we sought to provide a detailed quantification of postoperative bone regeneration. 223 CT records from 84 patients with initial bone cavity volumes exceeding 1000mm³ were included. 3D mandibular models were generated from the CT scans, and digital software was employed to measure cavity volume, surface area, and anatomical distances. The influence of cyst size, gender, and age on healing outcomes was evaluated at various intervals. Mandibular bone cavities healed most rapidly during the first three months, shrinking by approximately 1.14mm/month (IQR: 0.66-1.53mm/month) while bone volume increased by 0.61mm/month (IQR: 0.39-1.12mm/month). By three months, approximately 58.32% (IQR: 37.54-65.87%) of the cavity volume had healed. By 12 months post-operation, cavities were nearly healed with a healing rate of 90.23% (IQR: 80.69-94.45%). Bone accumulation was influenced by gender (P < 0.001), age (P = 0.014), cavity size (P = 0.004), and position (P = 0.029), with cavity shrinkage more significantly affected by the initial cavity size (P = 0.015) and gender (P = 0.004). Newly formed bone contributed to 63.28%(IQR:45.78-83.68%) of the total healing. This study offers a comprehensive 3D evaluation of mandibular bone healing after cyst enucleation. Both bone formation and cavity shrinkage were key components of healing. The study provides valuable insights for monitoring postoperative recovery and predicting bone healing.

Phase stable OCT with a 1050 nm tunable VCSEL and photonic integrated circuit

A turnkey phase-sensitive swept-source optical coherence tomography (OCT) system requires stabilization of both the swept source and main signal interferometer. We have provided stable clocking and triggering of a 1050 nm swept micro-electromechanical system (MEMS) vertical cavity surface emitting laser (VCSEL) by mounting a solid clock etalon and volume Bragg grating optical trigger inside a temperature-stabilized butterfly package. A photonic integrated circuit (PIC) provides a phase-stable main interferometer near the sample. This system is only sensitive to the motion of the sample, not to the fibers leading to and from the PIC. We provide optical frequency domain reflectivity measurements of the PIC performance. We also demonstrate OCT imaging as well as static and dynamic phase measurements of a Kindle e-book reader electrophoretic display.

Effect of functional monomers on the binding properties of molecularly imprinted polymers (MIPs) for selective recognition of dexamethasone

AbstractThis study examined the feasibility of removing dexamethasone (DEX) from aqueous solutions using molecularly imprinted polymers (MIPs). The binding energy, used to evaluate the affinity between imprinted molecule and functional monomer, was calculated for DEX using molecular simulation via the density functional theory method. From this approach, three different functional monomers were tested: methacrylic acid, N‐(Hydroxymethyl) acrylamide, and 2‐hydroxyethyl methacrylate designated as MIP‐DEX1, MIP‐DEX2, MIP‐DEX3, respectively. All of them were prepared by the precipitation polymerization method, with trimethylolpropane trimethacrylate used as the crosslinker. Moreover, the kinetics of adsorption and adsorption isotherms were evaluated using different models to assess the adsorption mechanisms of DEX on polymers. The results showed that equilibrium between the polymer and DEX is reached at 180 min, with a maximum adsorption capacity of 117.27 mg g−1 for sample MIP‐DEX3. The kinetic studies indicated that the adsorption of DEX on the polymers fits very well with the pseudo‐second‐order kinetic model. Equilibrium data were best described by the Freundlich model, suggesting that the sorption process occurs on a heterogeneous surface of the polymer cavities. The thermodynamic study confirms the role of selectivity cavities, exhibited in the sample MIP‐DEX3. Reusability tests and application on real samples suggest that the synthesized polymers are promising adsorbents.Highlights The functional monomer was chosen using a semiempirical computational simulation. Three monomers were tested to study their influence on dexamethasone recognition. The molecularly imprinted polymers (MIPs) prepared from 2‐hydroxyethyl methacrylate achieved the maximum analyte adsorption. Our MIP exhibited a selectivity constant of 41.11 in the presence of cortisone. The prepared MIP was successfully reused and tested for dexamethasone in real water samples.

Free surface flows induced by re-entrant jet with surface tension effect in a channel

In this paper, we study the two-dimensional free surface cavity flows past a wedge in a channel. A re-entrant jet cavity termination model is introduced. Gravity is neglected, but surface tension is included in the dynamic boundary condition. The fluid is assumed to be inviscid and incompressible and the flow is assumed to be steady and irrotational. When the surface tension is negligible, we calculate an exact free streamline solution by applying conformal mapping techniques. We also compute solutions including the effects of surface tension by using the series truncation method. The results of calculations of the effect of the Weber number and the half angle of the wedge β \beta on the free surface profiles are presented. Good agreement between the analytic free streamline solution and the numerical solution provides a check on our numerical scheme.

Single-crystal CsPbBr3-based vertical cavity surface emitting laser.

All-inorganic perovskite materials have been widely used in various devices, including lasers, light-emitting diodes (LEDs), and solar cells, due to their exceptional optoelectronic properties. Devices utilizing high-quality single crystals are anticipated to achieve significantly enhanced performance. In this work, we present a high-performance vertical cavity surface emitting laser (VCSEL) based on a single-crystal CsPbBr3 microplatelet, fabricated through a simple solution process and sandwiched between two distributed Bragg reflector (DBRs). The VCSEL demonstrated single-mode lasing at 542 nm, a low threshold of 5 µJ/cm2, and a high Q-factor of 2893. Additionally, time-resolved photoluminescence (TRPL) measurements using a streak camera revealed picosecond-scale lasing dynamics. This study offers a novel, to the best of our knowledge, approach for realizing laser devices using perovskite single-crystal microplatelets.

Optimization of Mold Heating Structure Parameters Based on Cavity Surface Temperature Uniformity and Thermal Response Rates.

Rapid heating cycle molding technology has recently emerged as a novel injection molding technique, with the uniformity of temperature distribution on the mold cavity surface being a critical factor influencing product quality. A numerical simulation method is employed to investigate the rapid heating process of molds and optimize heating power, with the positions of heating rods as variables. The temperature uniformity coefficient is an indicator used to assess the uniformity of temperature distribution within a system or process, while the thermal response rate plays a crucial role in evaluating the heating efficiency of a heating system. The thermal response rate of the cavity and the temperature uniformity coefficient are set as optimization objectives to define parameter ranges for orthogonal experiments. The findings indicate that the optimal range for the lateral distance L1 is 20-30 mm, for L2 it is 50-70 mm, and for the vertical distance (h) it is 3-8 mm. The response surface multiple regression equation derived from the orthogonal experiment data demonstrates a model prediction error rate of 1.8% and 2.4%. Additionally, by applying particle swarm optimization to the regression equation, the study identifies an optimal scheme that reduces system energy consumption by 12.5%, achieves a thermal response rate of 0.75 k/s, decreases the temperature uniformity coefficient by 44.6%, and lowers the temperature difference by 52.17%. This optimization ensures efficient heating of the mold cavity, reduces energy consumption, and enhances the uniformity of the surface temperature distribution, ultimately improving the surface quality of the products.

Heterogeneous forecasting of chaotic dynamics in Vertical Cavity Surface Emitting Lasers with knowledge based photonic reservoir computing

Heterogeneous forecasting of chaotic dynamics in Vertical Cavity Surface Emitting Lasers with knowledge based photonic reservoir computing

Spiral and helical formation of passive and active polymers with stiffness heterogeneity in a spherical cavity.

Biomolecules usually adopt ubiquitous circular structures which are important for their functionality. Based on three-dimensional Langevin dynamics simulations, we investigate the conformational change of a polymer confined in a spherical cavity. Both passive and active polymers with either homogeneous or heterogeneous stiffness are analyzed in a comparative manner. For a homogeneous chain, continuous rigidity along the backbone promotes a flat spiral expanding along the cavity surface, while activity-induced softening results in a less-ordered spiral structure. Stiffness heterogeneity basically plays a destructive role in spiral formation. However, as the chain is endowed with activity, the heterogeneity effect depends on the stiffness of the front edge of the chain. As the head is rigid, the flat spiral largely holds, whereas such a structure easily loses as the head is flexible. More intriguingly, a short flexible head induces a distinct compact helix in the interior of the cavity. Under low friction conditions, the prominent inertial effect leads to the break-up of both spiral and helix. In the presence of crowding, the flat spiral close to the surface keeps its stability, while the compact helix inside tends to be dissolved. Our results decipher the significant effects of activity, rigidity, confinement and crowding on modulating polymer conformations, which provides a deeper insight about mechanisms for circular structure formation of biopolymers in crowded environments.

Research on high-speed water entry similarity of multiscale vehicle based on two-parameter compensation of atmospheric pressure–density

The atmospheric pressure and density are important factors affecting the water entry cavity and load characteristics of the vehicle. However, it is difficult to take into account the equivalent simulation of the two in the scaled-down test. The use of atmospheric pressure–density two-parameter compensation may become a key means to achieve accurate scale similarity. In this paper, the evolution of the water entry cavity and the similarity of impact loads for multiscale models in different environments are studied. Aiming at the problem that the similarity conditions are difficult to meet in small-scale model test, a distortion compensation correction method is proposed. The results show that under normal pressure environment, as the scale ratio decreases, the cavity surface closes in advance, and the slamming load gradually decreases. Under reduced pressure environment, the influence of the “scale effect” is significantly reduced. As the pressure decreases, the cavity surface closure phenomenon is weakened, and the cushioning effect of the air cushion is reduced, resulting in an increase in the slamming load. Quantitative analysis shows that the atmospheric pressure mainly affects the pressure disturbance trend in the cavity, while the atmospheric density determines the scale of the cavity and the size of the model load. By adjusting the pressure and density parameters, the prediction deviation of the small-scale model test on the disturbance time of the prototype reentrant jet pressure can be controlled within 2.4%.

A small cavity for detecting sound-induced flow.

A study is presented of a method for creating an acoustic flow sensor that is generally compatible with current silicon microfabrication processes. An aim of this effort is to obtain a design consisting of a minimal departure from the existing designs employed in mass-produced silicon microphones. Because the primary component in all of these microphones is the cavity behind the pressure-sensing diaphragm, we begin with a study of the acoustic particle velocity within a cavity in a planar surface. The sound within the cavity is caused by the external plane sound wave traveling parallel to the cavity's open surface. It is shown that with suitable dimensions of the cavity, the acoustic particle velocity simultaneously flows inward at one end and outward at the other end of the single open cavity surface. A simple analytical model is presented to estimate the required length and depth of the cavity such that the acoustic particle velocity into and out of the opening is a reasonable approximation to that of a plane traveling sound wave in the free field. Measurements of the acoustic particle velocity into and out of the cavity are in close agreement with both the simple model and a more detailed finite element model. Agreement between two dissimilar modeling approaches and experiments suggests that the dominant features of the system have been accounted for. By redirecting the acoustic particle velocity into and out of the cavity opening rather than the flow being parallel to the plane surface, this configuration greatly facilitates the design and fabrication of structures intended to sense the acoustic flow.

Boosting energy efficiency and selectivity of glucose oxidation toward glucuronic acid in high-frequency ultrasound using multicavity CuO catalytic cavitation agents

Reactive oxygen species generated from the inertial collapse of a gas bubble trapped on the surface of an MC-CuO cavity selectively oxidize glucose into glucuronic acid.

Thermal management broadband-emitting device based on VO2 applied in the mid-infrared band.

Mid-infrared thermal radiation has attracted attention due to its wide range of applications. Compared to the static process of thermal emission, if thermal radiation can be dynamically controlled, it would be more suitable for practical applications. Herein, we designed a controllable thermal emitter based on phase change materials. When the temperature changes from low to high, VO2 transitions from a dielectric state to a metallic state, and its imaginary part of the dielectric constant significantly increases, leading to differences in emission characteristics. At low temperatures, the device is in a low dielectric state and resonates weakly with incident light. The main emission comes from the bottom of the grating structure, with an emissivity of 0.21. At high temperatures, the structure is in a high dielectric state, and multiple resonance modes are excited within the structure, such as cavity resonance and surface plasmon resonance, which increases the emissivity to 0.95 and achieves effective heat dissipation. Given its superior thermal management capabilities and stability, this design holds promise for applications in thermal imaging, infrared communication, and energy-efficient devices.

Modeling of Multi Hermite‐Gaussian MDM Based Passive Star ITU G.989.x Standardardized PON System

ABSTRACTPassive optical network (PON) is one of the key enabling technologies to fulfill the latest exceptional bandwidth demand owing to an exponential rise of Internet data traffic induced by the expansion of bandwidth‐hungry applications services. The potential of using passive star topology for ITU‐T G.989.x standardardized next generation PON incorporating vertical cavity surface emitting laser input source, is proposed in this paper. Mode division multiplexing (MDM) technique employing Hermite‐Gaussian (HG10 and HG20) modes are used to enhance the channel capacity at bidirectional 80 Gbps traffic rate. By utilizing polarization mode dispersion (PMD) emulator, this proposed system is promising since it offers good tolerance ability of anti‐PMD, anti‐dispersion, suppression of nonlinear effects and high spectrum effectiveness at high‐speed transmission. Impressively, faithful 600 and 590 m range is obtained at HG10 and HG20 modes respectively, with clear eye patterns at bit error rate of 10−9 for 1596–1598.4 nm in downlink. In uplink, faithful 600 and 530–600 m distance is achieved for 1524–1526.4 nm at HG10 and HG20 respectively. For variable laser temperature, maximum tolerable temperature of 20°C for both modes in downlink and 20°C at HG10 as well as 14C at HG20 is observed in uplink, over 600 m range. Besides, the proposed design undergoes ∼1e‐30 at HG10 and ∼1e‐35 at HG20 coupling coefficients for linearly polarized (LP[0,1] to LP[−4,3]) modes. It is also analyzed that maximum 3.99 dB gain and 84.58 dB optical signal‐to‐noise ratio is obtained for the proposed scheme. This design does not suffer from shot, thermal and phase noise and offers optimum performance than existing systems.

High Power Multi-Junction 808 nm Vertical Cavity Surface Emitting Lasers With High Efficiency

High Power Multi-Junction 808 nm Vertical Cavity Surface Emitting Lasers With High Efficiency

Assessment of the effectiveness of a rotatable shank toothbrush compared to a conventional handle toothbrush: A multicenter, single-blind, randomized controlled trial.

The persistence of dental plaque is attributable to the inaccessibility to all surfaces of the oral cavity. Thus, an integrated team designed an innovative toothbrush comprising a brush head assembly with an upper end and a lower end, and a handle rotatably configured with the lower end of the brush head assembly. The brush head is connected to the handle through a socket-ball joint, which allows the shank and the handle to rotate at any angle between 0° and 360° with respect to one another around an axis. Additionally, the brush head bends toward the handle, maintaining a bending angle of 15°. The aim of the present randomized controlled trial (RCT) was to analyze and assess the effectiveness of a toothbrush with a rotatable shank in comparison to toothbrushes with flexible and straight handles with respect to supragingival plaque and gingival health outcomes. The secondary objective of the study was to evaluate the feedback of individuals who used the rotatable shank toothbrush. Three toothbrushes - one with a rotatable shank, one with a flexible handle and one with a straight handle - were compared in terms of efficacy in plaque and gingivitis control at 3 clinical centers (a multicenter trial). A total of 270 patients, aged 18-65 years, were included in the study. The collected data was analyzed and compared using the analysis of variance (ANOVA) with Tukey's post hoc test. All groups demonstrated improvement in gingival health and a reduction in the plaque index (PI) scores. Nonetheless, the improvement was more pronounced in the group that used the toothbrush with a rotatable shank. The enhanced plaque removal and improved gingival health at all surfaces achieved with the rotatable shank toothbrush are ascribable to the incorporation of 2 features: the ability to rotate the toothbrush neck along its axis; and an inclination that facilitates access to all surfaces.

Dynamic thermal performance of prefabricated temporary exterior wall using cooling water in the cooling season

The acceleration of urbanization has led to a continuous increase in various types of buildings. In the hot season, cooling systems cool buildings and improve their comfort. However, traditional cooling methods require more energy consumption and greenhouse gas emissions. This paper designs a prefabricated building exterior wall with embedded pipes based on water cooling system reduces the output of traditional cooling way in building cooling. The innovation of this research is using the embedded pipe to improve the thermal properties of exterior walls, bonging the embedded pipe and exterior wall structure together. The results show that the embedded prefabricated building exterior walls are designed to control the indoor wall temperature to around 28 ℃ in summer. And the temperature on the surface of the inner liner cavity is always above 25.5 ℃. The overall trend shows a decrease followed by an increase. At noon, the surface temperature on the cavity side of the inner lining plate is the lowest, about 25.8 ℃. The larger the indoor and outdoor temperature difference, the better the cooling effect of the structure on the building. This study's application can help reduce energy consumption and carbon emissions effectively.

Effects of Steam Explosion on Curcumin Extraction from Fresh Turmeric Chips.

The purpose of this research is to study the effect of the steam explosion (SE) process on curcumin extraction from fresh turmeric chips. Fresh turmeric chips abruptly disintegrated during the steam explosion process. The investigation into the turmeric particles following the steam explosion process in the SEM micrographs revealed that the formation of surface cracks and cavities led to an increase in the surface area of turmeric particles. Curcumin extracted from turmeric particles after the steam explosion process yielded 3.24% (w/w), which was comparable to the yield of 3.98% (w/w) from finely ground turmeric particles, while the steam explosion used 74% less energy than the grinding process. Therefore, the steam explosion process is an efficient process compared to untreated and conventional mechanical grinding methods. On average, the turmeric particles decreased in size when the dissipated energy per mass increased. The curcumin yield from the steam explosion exhibited a linear positive correlation with the dissipated energy per mass. FTIR, TG/DTG, and DSC analyses on the turmeric particles after the steam explosion process showed that the compounds exhibited no change in chemical structure, higher thermal decomposition properties, and higher purity, respectively. The results of this research can be applied to find optimal conditions for extracting curcumin and predicting the yield of curcumin. Additionally, they can be applied to evaluate the process condition in commercial applications.

Hydrodynamic characteristics of cavity fluctuation behind a cone-rod assembly entering water

This study explores the phenomenon of cavity fluctuation occurring behind a cone entering water at a constant velocity. The current simulations reveal that cavity fluctuations arise following deep pinch-off, leading to pronounced pressure oscillations in both the water and air regions. Concurrently, ripples form along the cavity surface, extending from the nose to the tail, resulting in a wavy cylindrical cavity. Notably, when the water entry Froude number is below 10, the load on the cone is predominantly due to pressure oscillations induced by cavity fluctuations, which exceed the slamming load experienced during initial water impact. The study also identifies a significant impact of an attached rod on cavity evolution. Specifically, the frequency of cavity rippling increases with the rod's radius; however, when the rod-to-cone radius ratio is less than 20%, the rod's impact on the cavity dynamics becomes negligible. A theoretical analysis, modeling the cavity as a hollow cylindrical structure, is developed to elucidate the relationship between rippling frequency and rod size. The research results demonstrate that the cavity fluctuation frequency is inversely proportional to the difference in the squared radii of the cone and rod. Furthermore, when the scaling length of the cavity at the pinch-off moment exceeds a ratio of Lp/Rc &amp;gt; 6, the water entry cavity can be accurately modeled as a long cylindrical cavity. The numerical results confirm that the proposed theoretical model provides reliable predictions of the impact of a solid rod on the fluctuation characteristics of the cavity.

Development of eDART based online diameter prediction systems in injection molding with multiple linear regression and fuzzy logic

Abstract Injection molding is a versatile technique for processing a wide range of thermoplastic and thermosetting polymers, as well as their composites. Dimensional defects are a critical issue in injection molding. This research focuses on developing online diameter prediction systems via multiple linear regression (MLR) and fuzzy logic. The systems are developed using Delrin 311 DP material, with the Taguchi methodology employed to define optimized process parameters that ensure adequate process capability. Processing data were collected from the sensors embedded in the surface of mold cavity by the eDART system. Regression analysis was employed to build and test the relationship between the real-time data from in-mold sensors and the diameter of molded part. The real time data from the sensor-based monitoring system, including end of cavity, hydraulic injection pressure, and efficient viscosity, were selected as the inputs for the predictive model. Both MLR and fuzzy logic models were established to predict the outcomes, based on the data retrieved from the sensors, achieving the prediction accuracies of 99.09% for MLR and 99.98% for fuzzy logic, respectively. Fuzzy logic demonstrated its reliability in predicting diameters and minimizing dimensional defects in injection molding.