Index Matching Research Articles

Monitoring of crack-induced electromagnetic vector field based on tunnel magnetoresistance effect

Electromagnetic radiation technology is widely used as a non-destructive, non-contact monitoring method, but the spatial information contained in it is ignored. A three-axis electromagnetic sensor was developed to monitor the electromagnetic radiation generated by the fracture of brittle rocks based on the tunnel magnetoresistance effect. The sensor has significant independence, anti-interference in three orthogonal directions, and exhibits high linearity. The monitored signals can be regarded as the components of the electromagnetic field vector in three directions. Based on the idea of vector synthesis, the peak index and peak matching index of the synthesized signal are extracted for the directional characterization and can be used to identify the direction of cracks.

A Radio-loud Semiregular Variable

As a byproduct of our search for Galactic stellar systems with gamma-ray emission, we have identified an unrelated cool and evolved star (IRC-10412) that attracted our attention due to its strong radio emission level with a spectral index matching, almost perfectly, the canonical +0.6 value expected from an ionized stellar wind. A follow-up observational analysis was undertaken given that these two properties are hard to reconcile as originating in the same stellar object. As a result, IRC-10412 has been classified as a new semiregular variable of SRb type in the asymptotic giant branch, and different but consistent estimates of its mass-loss parameter are reported. We propose that its unusually high radio emission arises from a ∼10−5 M ⊙ yr−1 stellar wind exposed to an external source of ionizing photons, possibly coming from nearby OB associations.

Deformation Characteristics and Influence Factors of Shear Force Lateral Stiffness Matching Index for Non-Rigid Plate Bent Frame Structures

The period ratio and the drift ratio are commonly used as plane regularity control indices for multi-story buildings. However, they fail to reasonably reflect the regularity of lateral force-resisting component configuration and deformation characteristics in non-rigid plate bent frame structures. This study focuses on the analysis of non-rigid single-span bent frames, examining the variation patterns of a suitable regularity index for non-rigid plate bent frame structures, referred to as the shear force lateral stiffness matching index, under various parameters. Additionally, it introduces indices to quantify the deformation response of non-rigid plate bent frame structures, providing a detailed analysis of the impact of factors such as eccentricity, torsional stiffness, and roof slab stiffness on the deformation characteristics of non-rigid plate bent frame structures and the shear force lateral stiffness matching index. The results show that the shear force lateral stiffness matching index can reflect the inconsistency in the horizontal displacement response of lateral force-resisting components caused by deformations in the roof slab. The proposed indices for torsional and bending deformations accurately quantify the roof slab’s deformation response, revealing the horizontal deformation characteristics of lateral force-resisting components in non-rigid frames. When eccentricity is present, the stiffness of the roof slab has a non-monotonic effect on the torsional component of the structural seismic response.

Impact of Diagnosis-Related Groups (DRG) reform on cost homogeneity of treatment for patients with malignant tumours

The cost fluctuations associated with chemotherapy, radiotherapy, and immunotherapy, as primary modalities for treating malignant tumors, are closely related to medical decision-making and impose financial burdens on patients. In response to these challenges, China has implemented the Diagnosis-Related Group (DRG) payment system to standardize costs and control expenditures. This study collected hospitalization data from patients with malignant tumors who received chemotherapy, radiotherapy, and immunotherapy at Hospital H from 2018 to 2022. The dataset was segmented into two groups: the intervention group, treated with traditional Chinese medicine (TCM) alongside standard therapies, and the control group, treated with standard therapies alone. Changes and trends in hospitalization costs under the DRG policy were analyzed using propensity-score matching (PSM), standard deviation (SD), interquartile range (IQR), and concentration index (CI). Findings showed a decreasing trend in the standard deviation of hospitalization costs across all treatment modalities. Radiotherapy exhibited the most significant decrease, with costs reducing by 2547.37 CNY in the control group and 7387.35 CNY in the intervention group. Following the DRG implementation, the concentration indexes for chemotherapy and radiotherapy increased, while those for immunotherapy did not exhibit this pattern. Costs were more concentrated in patients who did not receive TCM treatment. In summary, DRG reform positively impacted the cost homogeneity of inpatient treatments for malignant tumors, particularly in the control group not receiving TCM treatment. The effects of DRG reform varied across different treatment modalities. Although short-term fluctuations in hospitalization costs may occur, initial evidence during the study period shows the positive impact of DRG reform on cost homogeneity.

Linkage and Demographic Indexing for Nursing Dynamics in the Integrated Data Service

Objective and ApproachThis project links UK Nursing and Midwifery Council (NMC) Registrant data to the 2021 England and Wales Census (“Census 21”). The Office for National Statistics (ONS) has composed a framework of index tables to facilitate linkage between prominent datasets in the UK. In linking person-level data to Census 21, ONS’ Demographic Index enables onward linkage to other administrative datasets that are indexed alike. NMC Register and Census 21 records have been initially linked using bespoke deterministic and probabilistic methods, with resulting matches being joined to the Demographic Index. ONS’ Demographic Index Matching Service (DIMS) will also be used to link NMC data to the Demographic Index to enable comparisons between methods. ResultsAnalysis of both approaches will compare quality metrics such as match rate, recall and precision and tools will be used to assess bias in matches made through each method. These metrics will provide an insight into how the index matching services have been designed and whether improvements can be made to account for any shortcomings in their performance. ConclusionsHybrid approaches using both bespoke and indexing methods are proving valuable where sole use of the matching services is not suitable. This research will help ONS to refine which methods will yield the highest quality linkage and when. ImplicationsAs ONS pursues an ‘indexing first’ approach to linkage, the outcomes of this and similar projects will influence the future of utilising indexes in varied capacities when creating or maximising the potential of linked data.

Management on Transfer Pricing of Farmland Based on the Supply–Demand Mismatches for Multifunction: A Case Study from China

Realizing the multifunctional value of farmland is essential for regulating the pricing of farmland transfers and stabilizing the rural land market. However, in China, the mismatch between supply and demand leads to improper resource allocation, weakens the explicit value of farmland, and causes unreasonable transfer pricing mechanisms that threaten agricultural production and food security. This study develops an analytical framework to examine the relationship between farmland multifunction and transfer pricing from a supply–demand perspective. An evaluation index system is constructed, considering the physical, value, and material quantities. This study uses the matching index method and bivariate spatial autocorrelation to analyze the supply–demand match of farmland multifunction from 2014 to 2021 and its relationship with transfer prices. Additionally, management methods and strategies for dynamic zoning-based pricing under multifunctional matching trade-offs are proposed. The results show that: (1) There is significant heterogeneity in the supply and demand matching degree of different farmland functions in both space and time. The production and ecological functions of farmland are oversupplied, while the living functions are undersupplied. (2) Different spatial autocorrelation relationships exist between the degree of supply and demand matching of farmland functions and farmland transfer prices. Specifically, the supply and demand matching degrees of the production and living functions show a significant negative spatial correlation with farmland transfer prices. In contrast, the ecological function shows a significant positive spatial correlation with farmland transfer prices, which are continuously strengthening over time. (3) Based on the supply and demand matching situation of different farmland functions and the spatial autocorrelation of farmland transfer prices, nine types of regions are delineated for farmland functions. Among them, the surplus-coordinated development areas have the most cities, accounting for about 40%, with a wide distribution range. This study proposes zoning-based pricing instruments and management strategies. This research provides valuable insights for developing countries seeking to alleviate conflicts in multifunctional land use, enhance the sustainable protection of land resources, and improve land resource assessment frameworks.

Is there an association between the ‘October 7th’ events and IVF outcomes in Israel?

Research questionIs there an association between the ‘October 7th’ 2023 events and IVF outcomes in Israel? Designin this retrospective cohort study the study group was women treated during the 4 weeks after ‘October 7th’, compared with a matched control group treated between 1 January 2021 and 6 October 2023. Each study group participant was matched with three separate control subjects of the same female age at oocyte retrieval, with a matching body mass index (BMI), IVF cycle number and ovarian reserve parameters. ResultsThe study included 580 patients. The 145 women who underwent oocyte retrieval or frozen embryo transfer after 7 October 2023 were compared with 435 women treated before 7 October. The mean age of the study group was 35.6 ± 6 years, and the mean BMI 24.7 ± 5.3 kg/m2. Pregnancy rates per embryo transfer were similar between the groups (22.4% versus 30.5%, P = 0.28 in fresh cycles; 16.9% versus 27.1%, P = 0.12 in frozen embryo transfers). Among women who underwent oocyte retrieval there were no differences in the ovarian stimulation protocols (P = 0.95), number of oocytes retrieved (P = 0.16) or number of fertilized oocytes (P = 0.34). There was no difference in the rate of good-quality embryos between groups (P = 0.053). Among women who underwent frozen embryo transfers, during the study period more patients had natural cycles (52.5% versus 24%, P < 0.001), and there was no difference in maximal endometrial thickness before embryo transfer (P = 0.33). ConclusionsIt appears that there is no association between the ‘October 7’ events and IVF outcomes.

A facile route to fabricate transparent and mechanically robust glass-fabric reinforced composites via refractive index matching and tow-spreading technique

There are challenges to fabricate GFRPs with high optical clarity and mechanical performance due to the inevitable chromatic dispersion and yarn crimp in the fabric. Herein, a facile route to fabricate transparent glass-fabric reinforced composites is reported using refractive index matching and tow-spreading technique. By introducing different amount of BMA, the epoxy matrix could match the refractive index of glass fibers at different wavelength. The fabricated composites exhibit intriguing pale blue/blue, dark blue/ purple, purple-pink/pink chromatic dispersion, respectively. Among them, the 0.2 mm-thick GFRP with 4 % BMA (fiber volume fraction ≈ 50.4 %) exhibits the highest total transmittance (89.5 %) and lowest haze (3.4 %). Compared with commercial standard-tow fabric, composites with spread-tow fabrics exhibits less chromatic dispersion and transparency loss. Moreover, simultaneously reinforcing and toughening effect could be observed in the composites with BMA modified matrix. The optimized composites possess tensile strength of 289 MPa and flexural strength of 416 MPa.

Temporal Evolution of Interparticle Potentials of PMMA Colloids in CHB/Decalin.

Colloidal dispersions composed of polymethylmetacrylate particles dispersed in a mixture of cyclohexyl bromide and decalin find widespread use as model systems in optical microscopy experiments. While the system allows simultaneous density and refractive index matching, preparing particles with hard potentials remains challenging, and strong variations in the physical parameters of samples prepared in the same manner are commonly observed. Here, we present data on the measurement of forces between individual pairs of particles in highly diluted dispersions over the course of tens of days using the blinking optical tweezers method. Our results show that the variations in the particle properties are indeed caused by a temporal evolution of the particles' charging. Additional measurements of the influence of the addition of tetrabutylammonium bromide (TBAB) to the dispersions show that already small concentrations of added TBAB salt drastically decrease the electrostatic forces between colloidal particles. However, small, non-negligible contact potentials remain even at the highest TBAB concentrations added.

Applications of RIM-Based Flow Visualization in Fluid-Solid Interaction Problems: A Review of Formulations and Prospects

Over the past three decades, optical visualization measurements based on the Refractive Index Match (RIM) method have played a significant role in the experimental studies of fluid-solid interaction. The RIM method, which coordinates the refractive indices of the liquid and solid materials in the experiment, dramatically reduces the observation error due to optical refraction. However, the existing literature on RIM has not systematically reviewed the various applications of this technique. This review aims to fill this gap by providing a comprehensive overview of the RIM technique, examining its role in material selection for fluid-solid interaction studies, and scrutinizing its applications across various engineering disciplines. The paper begins with a brief introduction to the RIM technique and then turns to material selection and its various applications in fluid-solid interaction. It also enumerates and analyzes specific RIM-based optical measurement techniques such as Laser Doppler Velocimetry (LDA), Particle Tracking Velocimetry (PTV), and Particle Image Velocimetry (PIV) from various research perspectives in previous studies. In addition, it summarizes RIM formulations categorized by different applications in liquid-solid interaction fields. RIM-based measurement techniques generally offer intuitive, non-intrusive, cost-effective, and convenient advantages over traditional methods. The paper also critically evaluates the strengths and limitations of different materials used in RIM experiments and suggests directions for future research, emphasizing the need to develop environmentally friendly and cost-effective RIM materials.

Transparency-changing elastomers by controlling of the refractive index of liquid inclusions

Complex materials that change their optical properties in response to changes in environmental conditions can find applications in displays, smart windows, and optical sensors. Here a class of biphasic composites with stimuli-adaptive optical transmittance is introduced. The biphasic composites comprise aqueous droplets (a mixture of water, glycerol, and surfactant) embedded in an elastomeric matrix. The biphasic composites are tuned to be optically transparent through a careful match of the refractive indices between the aqueous droplets and the elastomeric matrix. We demonstrate that stimuli (e.g., salinity and temperature change) can trigger variations in the optical transmittance of the biphasic composite. The introduction of such transparency-changing soft matter with liquid inclusions offers a novel approach to designing advanced optical devices, optical sensors, and metamaterials.

GTDIM: Grid-based Two-stage Dynamic Incentive Mechanism for Mobile Crowd Sensing

Mobile Crowd Sensing (MCS) technology, as an emerging data collection paradigm, offers distinct advantages, particularly in applications like smart city management. However, existing researches inadequately address the comprehensive solution to the problem of reliable task allocation according to the requirements such as task budget, sensory data quality, and real-time data collection, especially under varying participant engagement in MCS systems. To bridge this gap, we propose the Grid-based Two-stage Dynamic Incentive Mechanism (GTDIM). In the first stage, the Candidate Participant Set (CPS) establishment phase, participants receive compensation for collecting sensory data when a sufficient number are available. When participants are insufficient, additional rewards inspired by the grid division of sensing areas are progressively offered to attract more participants. In the subsequent stage, utilizing the established CPS, participants are selected through a greedy algorithm based on the newly devised Participant Matching Index (PMI), which integrates various participant features. Extensive simulation results reveal the impact of PMI on participant selection. Numerical findings conclusively demonstrate GTDIM’s superior performance over baseline incentive mechanisms in terms of task assignment ratio, participant payment, and especially when dealing with larger sensing tasks.

A Refractive Index Matched Experimental Investigation Of The Dynamics Of Inertial Spheres Across Round Pipes And Buoyancy-Driven Flows

A series of refractive index-matched time-resolved tomographic PIV experiments are performed to study the dynamics of motion of solid spheres in flow. The refractive index matching of acrylic spheres with the working fluid facilitates unobstructed optical access around the spheres, enabling the simultaneous estimation of both the 3D flow field and the fluid-structure interactions governing the kinematics of the spheres. Additionally, using normal tracers as well as fluorescent tracers for PIV helps identify the most suitable approach for multiphase index-matched PIV studies. Two different test cases are presented: (1) solid spheres moving in a round channel with an abrupt area expansion and, (2) solid spheres rising in a quiescent flow at terminal velocity. Despite both falling under the category of solid-liquid flows, these cases exhibit entirely different mechanisms and flow characteristics. Nonetheless, refractive index matching provides a valuable tool that can be used to characterize the flow as well as the motion dynamics of the free spherical particles in a liquid. These time-resolved 3D experiments offer a comprehensive insight into the transient evolution of the flow fields and the pressure forces on the spheres, providing a complete picture of the dynamic process. The emphasis of the present paper lies in the experimental methodologies, challenges and data analysis techniques used for refractive index-matched multiphase flow studies.

The impact of digital finance on young People's health insurance participation decisions in China.

The digital finance era has reshaped young people's lifestyles, risk perceptions and insurance participation decisions. Modern youth have to constantly seek for rational social security support and construct individual protection barriers to adapt to new lifestyles and social structures. China's multi-tiered, universal health insurance system is urgently needed to satisfy young people's flexible needs and rational decision-making. Based on the micro data from 2011 ~ 2021 Chinese General Social Survey (CGSS), this paper uses macro data from Digital Inclusive Finance Index (DIFI) matching to construct probit and m-logit model to assess the impact of the development of digital finance on Chinese youth whether or not to participate in health insurance, and how they choose the concrete type of health insurance. (1) Baseline regression results shows that digital finance has a significant positive effect on Chinese youth's health insurance participation decisions, and has different effects on choices within health insurance types. Strong support for the conclusions is provided by endogeneity and robustness tests. (2) The results of the heterogeneity analysis reveal that the marginal effect of digital finance on young people's health insurance decisions shows urban-rural differences, divergence in levels of self-rated health. (3) The mechanism analysis results suggest that there are two mechanism paths of digital finance on youth health insurance decisions: the household income effect and the subjective well-being effect, and two moderating effects: employment type and family structure. Highlighting the positive value that digital finance brings to the perception of youth insurance participation and the construction of social security systems, it needs to pay close attention to the dynamic changes in employment security and family structure through data, and explore the socio-psychological fluctuation and demand for social security among modern youth. To provide a way forward to achieve the integration of the health insurance system in China and solve the current problem of health insurance equity.

Supramolecular self-assembling hydrogel based on imidazole/d-sorbitol deep eutectic solvent for tissue clearance

Embedding and tissue clearing with high refractive index reagents are essential for 3D tissue imaging. However, the current liquid-based clearing condition and dye environment suffer from solvent evaporation and photo-bleaching, causing difficulties in maintain the tissue optical and fluorescent features. In traditional embedding technique, paraffin is highly astigmatic and paraffin-tissue complex is opaque; CLARITY series of gel-type tissue transparency methods usually achieve cross-linking of tissue and gel network first, and then active or passive degreasing by using SDS, TritonX-100 and so on, and finally, the tissue achieves a transparent state by refractive index matching. Based on high permeability of deep eutectic solvents (DES) and the optical transparency potential of polyols, this study developed a DES self-assembled hydrogel-based copolymer to embed mouse tissue for clearing and imaging prepared with imidazole and d-sorbitol. In addition to preserving the high optic transparency of the tissue, the DES hydrogel system is compatible with multiple fluorescence labeling, particularly lipophilic dyes. This DES hydrogel system provides a unique opportunity for simultaneous tissue embedding and clearing. The self-assembled hydrogel achieves 3D imaging at a solid state, and 2D images can be obtained through slicing after 3D imaging of complete organs. Due to its temperature dependent hydrogel properties, the hydrogel-tissue complex achieves gel-sol transition and allows tissue reuse. This transparent and hydrogel condition provides a friendly tissue and cellular environment to facilitate high resolution 3D imaging, preservation, transfer, and sharing among laboratories to investigate the morphologies of interest in experimental and clinical conditions.

Multilayer all-dielectric metasurfaces expanding color gamut

Abstract Structural color, arising from the interaction between nanostructures and light, has experienced rapid development in recent years. However, high-order Mie resonances in dielectric materials often induce unnecessary sub-peaks, particularly at shorter wavelengths, reducing the vibrancy of colors. To address this, we have developed a multilayer dielectric metasurface based on silicon-rich silicon nitride (SRN), achieving expanded color gamut through precise refractive index matching and suppression of high-order resonances. This strategy introduces more design dimensions and can reduce the complexity of material deposition. It enables the generation of vibrant colors in a 3 × 3 array, with a resolution of approximately 25,400 dpi, demonstrating its potential applications in displays.

First development of transparent wood-based triboelectric nanogenerator (TW-TENG): Cooperative incorporation of transparency, aesthetic of wood, and superior triboelectric properties

The combination of triboelectric nanogenerator (TENG) and wood-based materials offers a sustainable strategy for energy harvesting. The main challenge in realizing wood-based TENG is to increase the polarizabilities of wood. Herein, we introduce the first instance of a transparent wood-based triboelectric nanogenerator (TW-TENG), which synergistically incorporates superior triboelectric properties, optical properties, and aesthetic of wood. Addressing the challenges of weak polarizability and opacity inherent in natural wood, we propose a functionalized modification approach involving delignification and impregnation with UV-curable resin. In this study, leveraging delignification and the strong electron-donating groups within the UV-curable resin, the electrical output performance of TW-TENG is improved by 6.5 times compared to that of natural wood, and maintains stability over 10,000 operational cycles. Moreover, the matching refractive index between the UV-curable resin and the wood substrate offers TW-TENG with high transparency, achieving an optical transmittance of up to 88.8 %, exhibiting the unique aesthetic value of transparent wood. Furthermore, we demonstrate the potential applications of TW-TENG in energy harvesting, sensor technologies, smart decorative materials, smart home systems, and beyond, exemplified through its utilization in electrical output generation by pressing, capacitor charging and discharging, and self-powered multiplexed sensing smart target shooter.

Optical bonding utilizing aqueous Al2O3–P2O5-lactate sol-gel adhesives

In the field of optical bonding, traditional optical adhesives typically contain toxic organic polymers and solvents, limiting their widespread application. Hence, there is an urgent need for environmentally friendly aqueous adhesives. While there have been efforts to develop green adhesives, few report their performances with optical substrates. The unique requirements for optical adhesives include: optically transparent; the refractive index match of the substrate; minimal stress during and after curing. This presents a challenge to ensure compatibility between green and optical. This study introduces a novel sol-gel adhesive derived from an Al2O3–P2O5-lactate system. This adhesive is biocompatible, uses water as the sole solvent. It exhibits exceptional optical clarity, with more than 99 % transparency in the visible light and near-infrared regions. Furthermore, it provides reliable bonding strength, particularly when bonded with sapphire crystal substrates, reaching a maximum of 5.96 MPa. Interfacial chemistry analysis reveals the critical role of acidic components (such as phosphoric and lactate groups) in adhesives accounted for the bonding mechanism. By increasing the molar ratio of phosphoric acid, the bonding strength of adhesive was significantly enhanced across various substrates. This sol-gel adhesive not only adheres to green chemistry principles but also shows promising potential for optical bonding applications.

Synergistic retrieval of mangrove vital functional traits using field hyperspectral and satellite data

Mangroves play a pivotal role in the attainment of United Nations Sustainable Development Goals. Leaf equivalent water thickness (EWT) and leaf mass per area (LMA) are vital functional trait parameters for monitoring heath status of mangroves. However, their inherent spectral response characteristics remain unclear, which presents a challenge for high-precision estimating EWT and LMA using remote sensing images. In this study, we attempted to synergistic retrieval of mangrove EWT and LMA using field hyperspectral and satellite data. Specifically, we proposed a novel Fractional-order assisted Spectral angle Analysis (FSA) approach to accurately identify sensitive spectral domains of EWT and LMA for three mangrove species based on in situ full-spectrum hyperspectral (350–2500 nm) data. We constructed a new spectral matching index (SMI) to screen the satellite-based sensitive spectral bands based on the field-based spectral domains, and further verified their feasibility of estimating EWT and LMA using three optical satellite sensors (Sentinel-2A, SDGSAT-1, and OHS-3D). Finally, we explored the effectiveness of combining SAR and thermal infrared (TIR) images with sensitive spectral bands on improving retrieval performance in estimating EWT and LMA, respectively. Results indicated that FSA approach could capture the sensitive spectral domains of EWT (1125–1868 nm) and LMA (1419–1999 nm) for three mangrove species. The SMI could effectively realize the spectral matching between field-based sensitive domains and satellite-based bands, and perform the synergistic retrieval of mangrove EWT (R2 = 0.65) and LMA (R2 = 0.70). Intriguing finding is that the additional TIR bands significantly enhanced the EWT and LMA inversion accuracy (R2 increased by 9.8 %–68.3 %) when compared to SAR images. We confirmed that EWT displayed an inverse trend of LMA with the flooding frequency increasing. Our works provide a scientific basis for protection and sustainable management of mangroves.

Porous structures impact on particle dynamics of non-Brownian and noncolloidal suspensions

This study aims to provide valuable insights into the impact of porous structures on particle dynamics in non-Brownian, non-colloidal suspension flows at very low Reynolds numbers. Two experimental approaches, Particle Image Velocimetry (PIV) with refractive index matching and Optical Flow Tracking Velocimetry (OFTV) were employed to analyze very dilute suspensions over various porous media models. The study considered three different porous structures with permeabilities ranging from 0.7 to 0.9 and three different thicknesses ranging from 0.2 cm to 0.5 cm, while the suspension bulk volume fraction was maintained at 3 %. In the PIV analysis, we observed that decreasing the porous permeability resulted in the maximum velocity location within the free flow region moving closer towards the interface between the flow and the porous media. We further quantified the effect of the porous structure on the suspension by characterizing interface properties, such as dimensionless slip velocity, shear rate, and slip length. These interface properties were found to be influenced by both the thickness and permeability of the porous media. Next, we analyzed particle migration due to the presence of porous structures using OFTV for very dilute suspensions of 1 %, 2 %, and 3 %, considering a porous medium with known physical properties and thickness. The study revealed two local concentration maxima: one within the free flow region on top of the rod arrays used to create the porous structure and a second along the rods' centerline inside the porous media model.