Internal Spacer Research Articles

Spatial Network Structure and Shift Path Prediction of Ecological Welfare Performance in Chinese Cities—Evidence from 284 Cities

Ecological welfare performance (EWP) serves as a crucial measure for assessing the green development of a region. Exploring the spatial characteristics, network structure, and transfer paths of its specific stages is crucial for grasping an internal space’s EWP and optimizing urban ecological planning. This research employed a two-stage DEA model to assess the EWP of 284 Chinese cities from 2007 to 2022 and decompose it into an ecological–economic transition stage (L1) and an economic welfare transition stage (L2). Second, a social network analysis (SNA) was conducted to describe the EWP sub-stages’ network structure and construction mechanism. Finally, the transmission path process of EWP was revealed through Markov chains. It is found that (1) the overall trend of EWP is rising and then falling, with L2 as the critical constraint; (2) the network structure of the two stages is complex, dominated by industrial structure, urbanization, and healthcare level; and (3) ‘club integration’ constrains the transfer across EWP in the short term. Compared with L2, which has a lower probability of interstate transfer, L1 has a greater likelihood of transfer to a higher level. This paper provides suggestions for the optimal allocation of ecological resources in Chinese cities through the analysis of EWP.

On the universal exceptional structure of world-volume theories in string and M-theory

A universal structure of world-volume theories of 12-BPS branes in string and M-theory in terms of exceptional generalised geometry is observed. Previous constructions are extended in two ways: from internal d-dimensional space to full 11- or 10-dimensional spacetimes, by coupling to the tensor hierarchy gauge fields, and from Ed(d) with d≤6 to E7(7) and E8(8). This is done by a clarification of the role of the tensor hierarchy and its end in the context of brane world-volume theories. The exceptional structure of the gauged σ-model of the Kaluza-Klein monopole is provided as a new example.

Space in Music: what we call ‘space’ in music and what it really is

This article proposes a division of the concept of space in music into four spaces, namely the internal, external, intrinsic and extrinsic spaces. Having reviewed these concepts in texts from numerous authors and composers, we aggregate a variety of concepts into these four main categories of space in music. We also present possible transgressions of the boundaries of these concepts, with the understanding that these transgressions are common practice for contemporary composers. Currently, these practices of transgression tend to be confused because of the lack of a clear definition for the spaces in question.

The Impact of Scale on Extracting Individual Mobility Patterns from Location-Based Social Media.

Understanding human movement patterns is crucial for comprehending how a city functions. It is also important for city planners and policymakers to create more efficient plans and policies for urban areas. Traditionally, human movement patterns were analyzed using origin-destination surveys, travel diaries, and other methods. Now, these patterns can be identified from various geospatial big data sources, such as mobile phone data, floating car data, and location-based social media (LBSM) data. These extensive datasets primarily identify individual or collective human movement patterns. However, the impact of spatial scale on the analysis of human movement patterns from these large geospatial data sources has not been sufficiently studied. Changes in spatial scale can significantly affect the results when calculating human movement patterns from these data. In this study, we utilized Weibo datasets for three different cities in China including Beijing, Guangzhou, and Shanghai. We aimed to identify the effect of different spatial scales on individual human movement patterns as calculated from LBSM data. For our analysis, we employed two indicators as follows: an external activity space indicator, the radius of gyration (ROG), and an internal activity space indicator, entropy. These indicators were chosen based on previous studies demonstrating their efficiency in analyzing sparse datasets like LBSM data. Additionally, we used two different ranges of spatial scales-10-100 m and 100-3000 m-to illustrate changes in individual activity space at both fine and coarse spatial scales. Our results indicate that although the ROG values show an overall increasing trend and the entropy values show an overall decreasing trend with the increase in spatial scale size, different local factors influence the ROG and entropy values at both finer and coarser scales. These findings will help to comprehend the dynamics of human movement across different scales. Such insights are invaluable for enhancing overall urban mobility and optimizing transportation systems.

Effect of Nanoporous Molecular Sieves TS-1 on Electrical Properties of Crosslinked Polyethylene Nanocomposites.

Crosslinked polyethylene (XLPE) is an important polyethylene modification material which is widely used in high-voltage direct current (HVDC) transmission systems. Low-density polyethylene (LDPE) was used as a matrix to improve the thermal and electrical properties of XLPE composites through the synergistic effect of a crosslinking agent and nanopore structure molecular sieve, TS-1. It was found that the electrical and thermal properties of the matrices were different due to the crosslinking degree and crosslinking efficiency, and the introduction of TS-1 enhanced the dielectric constants of the two matrices to 2.53 and 2.54, and the direct current (DC) resistivities were increased to 3 × 1012 and 4 × 1012 Ω·m, with the enhancement of the thermal conductivity at different temperatures. As the applied voltage increases, the DC breakdown field strength is enhanced from 318 to 363 kV/mm and 330 to 356 kV/mm. The unique nanopore structure of TS-1 itself can inhibit the injection and accumulation in the internal space of crosslinked polyethylene composites, and the pore size effect of the filler can limit the development of electron impact ionization, inhibit the electron avalanche breakdown, and improve the strength of the external applied electric field (breakdown field) that TS-1/XLPE nanocomposites can withstand. This provides a new method for the preparation of nanocomposite insulating dielectric materials for HVDC transmission systems with better performance.

About gravitational radiation of semi local strings with non compact internal modes

The present work studies the gravitational radiation of a non abelian vortex with a non compact internal moduli describing its excitations. This situation may be realised by semi-local supersymmetric vortices [1]–[8], although supersymmetry is not necessary for this to happen. In the situation considered along this work, the internal space has infinite volume, and a largely energetic perturbation propagates along the object, even though the vortex line may not be moving. A specific configuration is presented, in which the internal space is the resolved conifold with its Ricci flat metric. The curious feature about it is that it corresponds to a static vortex, that is, the perturbation is only due to the internal modes. Even being static, the emission of gravitational radiation is in the present case of considerable order. This suggest that the presence of slowly moving objects that can emit a large amount of gravitational radiation is a hint of non abelianity.

P‐76: The Influence of Bending FFC Transmission Line on High‐Speed Signal Channels

Generally, display devices interconnect FFC transmission lines with circuits to form a transmission line network system to achieve data communication between Tcon and Driver. Due to the limitations of the external shape and internal space structure of the display device, the FFC transmission cable presents a curved shape from 0 to 180 degrees during the wiring process. Under the action of spatial electromagnetic fields, the display device will involve the field‐circuit hybrid problem of electromagnetic coupling of the FFC transmission line's bent line and circuit conduction interference, which will cause severe electromagnetic interference(EMI), resulting in deterioration of the high‐speed channel signal at the receiving end and even inability to correctly restore and decode the signal, thus causing signal distortion, which in turn leads to display image distortion or pixel loss.

Damage effects of aluminum alloy honeycomb sandwich panel double-layer structure induced by reactive projectile hypervelocity impact

In this paper, the experiments of Al2024 and reactive projectiles with hypervelocity impact on aluminum alloy honeycomb sandwich panel double-layer structure respectively were carried out by using two-stage light-gas gun, and the impact processes were recorded through high speed camera. According to the analysis of the experimental results, the debris clouds motion process and the damage effects on double-layer structure were compared. The damage enhancement mechanism of reactive projectile was revealed through numerical simulation and theoretical methods. The impact-induced detonation reaction of the reactive projectile can significantly reduce the "channel effect" of the honeycomb sandwich panel by destroying the honeycomb core cell wall, increase the perforation on the back facesheet of the honeycomb sandwich panel, and generate the debris cloud with higher temperature and faster expansion velocity. The debris cloud induced by the reactive projectile has a larger load distribution area on the rear plate, avoiding the concentration of loads in the center of the rear plate, and cause large area impact and thermal combined damage effects on the rear plate and internal space of the double-layer structure, while ensuring that the target structure cannot be penetrated. The reactive projectile efficiently applies the kinetic energy and chemical energy released by the impact-induced reaction to the interior of the target structure, the waste of kinetic energy caused by whole structure penetration can be avoided, resulting in significantly higher damage effects than the inert Al2024 projectile.

Tuning the interlayer spacing of graphene oxide membrane via surfactant intercalation for ultrafast nanofiltration

A facile method has been developed to fabricate lamellar composite graphene oxide (CGO) membranes by incorporating positively charged surfactants – cetyltrimethylammonium bromide (CTAB). The interlayer spacing of GO nanosheets was regulated by the sum of both vertical and horizontal alignment of CTAB on the GO surface via electrostatic interaction. The CTAB intercalated GO membrane exhibited an internal layer spacing of 16.97 Å compared to 8.26 Å for the GO membrane. The obtained CGO lamellar membrane with well-defined nanochannels showed ultrafast pure water flux of ∼1112 L h−1 m−2 bar−1 and an excellent separation efficiency of >99 % towards negatively charged organic dye molecules at a high permeation flux of ∼932 L h−1 m−2 bar−1, which was nearly 2.5-fold enhancement compared with that of the pristine GO membrane (∼400 L h−1 m−2 bar−1). The electrostatic and π–π interaction forces between the CGO membrane and organic dye molecules played a major role in the overall dye separation mechanism. Furthermore, the CGO membrane demonstrated excellent stability with no loss in separation performance (>96 % organic molecules rejection) after exposure to various pH solutions and deionized water (DI) water. The current work provides a straightforward approach for the formation of highly tunable and stable CTAB-intercalated GO membranes for ultrafast molecular separation.

Internal thread defect detection system based on multi-vision.

In the realm of industrial inspection, the precise assessment of internal thread quality is crucial for ensuring mechanical integrity and safety. However, challenges such as limited internal space, inadequate lighting, and complex geometry significantly hinder high-precision inspection. In this study, we propose an innovative automated internal thread detection scheme based on machine vision, aimed at addressing the time-consuming and inefficient issues of traditional manual inspection methods. Compared with other existing technologies, this research significantly improves the speed of internal thread image acquisition through the optimization of lighting and image capturing devices. To effectively tackle the challenge of image stitching for complex thread textures, an internal thread image stitching technique based on a cylindrical model is proposed, generating a full-view thread image. The use of the YOLOv8 model for precise defect localization in threads enhances the accuracy and efficiency of detection. This system provides an efficient and intuitive artificial intelligence solution for detecting surface defects on geometric bodies in confined spaces.

Pressure propagation mechanism of open-cell aluminium foam within a pipe under hypervelocity impact

Low-density open-cell aluminium (Al) foam exhibits a different deformation mode under hypervelocity impacts compared to being subjected to medium-low speed and quasi-static compression. In this case, material flows between cells in the form of metal jets and propagates forward. This paper establishes the open-cell Al foam model based on Voronoi tessellation. Using numerical methods, one-dimensional hypervelocity constant velocity impact experiments of 1–6 km/s inside a closed pipe are conducted on Al foam with different internal structure parameters (average cell diameter: 2–3.5 mm; ligament width: 0.251–1 mm). Propagation mechanism of pressure waves in foams and the key factors affecting the propagation velocity are investigated. Three zones are divided according to the condition of jet distribution along the impact direction: unaffected zone, jet influence zone, and particle accumulation zone. The variation of the length of different zones with impact velocity is discussed: higher velocities result in longer jet influence zones but shorter particle accumulation zones. Meanwhile, length of zones is closely related to the width of Al foam ligament and cell pore diameter: the larger the diameter of cell pores and the smaller the width of ligaments, the longer the length of the jet influence zone. Time dependence is exhibited in the length of jet influence zone for the large cell pore diameter specimens(≥0.03 cm). Particle pressures are extracted using the one-dimensional averaging method, which propagates forward significantly lower than in dense materials. Dominant factors affecting the pressure wave propagation of open-cell Al foam, i.e., the internal unloading space, are obtained by combining two-dimensional hypervelocity impact simulation experiments with different boundary conditions. A strong correlation between metal jet distribution and particle pressure propagation is observed.

The tune of shell numbers of multi-shell hollow mesoporous carbon microspheres for enhanced microwave absorption

The morphology of carbon nanomaterials plays significant effect on the complex permittivity and microwave absorption (MA) capability. Elaborate morphology design would bring about efficient MA performance. In this work, we develop a hollow mesoporous carbon microspheres with different shells (from single to quadruple shells) through a facile template method and layer-by-layer etching process. This multi-shell hollow mesoporous carbon microspheres (MS-HMCMs) can be regarded as a complex composite morphology consisting of hollow, mesoporous and yolk-shell structure, which presents the tunable number of shells for optimal impedance matching, multiple interfacial polarization and the extended microwave transmission path from internal spaces. Thus, the MS-HMCMs demonstrates wide effective absorption bandwidth (EAB) of 6.4 GHz and 5.96 GHz at the thicknesses of 2.5 mm and 3.0 mm. Besides, the complex permittivity and MA properties can be effectively tuned via regulating the shell numbers. This MS-HMCMs with controllable shells may be a promising wideband and lightweight microwave absorber.

Direct reconstruction of tissue temperature fields during thermal therapy by dynamic response matching and steady-state correction

In the field of oncology thermotherapy technology, online and real-time reconstruction of biological tissue temperature field is a fundamental work with important practical needs. In this paper, we proposed a new method for direct reconstruction of biological tissue temperature field by dynamic response feature matching and steady-state correction. Based on the bioheat transfer equation, the step response model of tissue temperature field during thermal therapy is established, and the dynamic response eigenvectors of biological tissue temperature and the steady-state gain of temperature response are determined offline. According to the optimal matching principle between the temperature dynamic response of the observation point and the internal space point of tissue, the optimal matching matrix of the dynamic response features between the observation point temperature and the internal temperature field of tissue is determined with the use of the dynamic response eigenvectors. Further, through the weighted synthesis of observation point temperature response by using the optimal matching matrix of dynamic response features, the tissue transient temperature field pre-estimation model is established. Finally, by correcting the tissue temperature field pre-estimation model with steady-state gain correction factor, the direct reconstruction scheme of temperature field based on dynamic response feature matching and steady-state gain correction is established. In this work, the non-destructive reconstruction of the internal temperature field of biological tissues during laser-induced thermal therapy is achieved based on the above direct reconstruction scheme. Numerical simulation experiments are performed to investigated the effects of pre-estimation time domain, the number of measurement points, laser irradiation form and measurement error on the temperature field reconstruction results.

Prognostic value of biohybrid screening results for assessing cancer risk using the example of lung cancer

Introduction. One of the leading places in the structure of socially significant diseases in the Russian Federation is occupied by malignant neoplasms, among which cancer of the trachea, bronchi and lung occupies the first place in terms of prevalence. Screening for lung cancer is not carried out at the federal level in Russia; recommended screening measures include questionnaires to identify risk factors for the development of the disease (including occupational) and the formation of dispensary observation groups. The study aims to assess the prognostic value of a new method of biohybrid screening of lung cancer by exhaled air. Materials and methods. Scientists conducted a study at the National Medical Research Center of Oncology of the Ministry of Health, Russian Federation, with the participation of 24 conditionally healthy volunteers and 5 patients diagnosed with lung cancer in the early stages of the disease. The design of the study is simultaneous (on-line) with blinding; experts estimated the risk of systematic errors at 10 points on the QUADAS scale. The authors examined exhaled air samples on a gas analyzer (biohybrid detector) of the BGS-APK 02SZZ model, in which the sensor were animals — gray domesticated rats (Rattus norvegicus) with microelectrode matrices implanted into the olfactory bulb, and which were in the internal (ventilated) space of the analyzer in a state of drug anesthesia. The conclusion about the presence or absence of a risk of lung cancer was formed by an artificial neural network of the analyzer, at the input of which bioelectric signals from each microelectrode were received, which were preprocessed using a system for recording the focal activity of the olfactory analyzer. The specialists confirmed the presence or absence of a risk of lung cancer by a reference method, according to computed tomography of the chest in accordance with the Lung Imaging Reporting and Data System (LungRADS™). Results. During the study, experts determined the effectiveness indicators of the method of biohybrid lung cancer screening by exhaled air: sensitivity (64%), specificity (87%), prognosticality of negative and positive conclusions about the presence/absence of disease risk (82% and 72%, respectively). Conclusion. The safety, efficiency and throughput of the investigated method, together with the reproducibility of the analyzer's conclusions, meet the criteria of practicability to ensure the first (population-based) stage of lung cancer screening.

Theoretical study on photoelectric properties of ferroelectric photovoltaic perovskite CsGeBr3 based on first-principle calculations

Ferroelectric photovoltaic materials have attracted great attention because of their unique photoelectric conversion mechanism, high photo-generated voltage, and adjustable polarization intensity. Traditional ferroelectric oxide perovskites such as BaTiO3, BiFeO3, and Pb(ZrTi)O3 have attracted much attention but they are not suitable as light absorbing layers in solar cells, due to the large optical bandgap, low light absorption rate, and small photogenerated current. Therefore, it is necessary to seek prominent materials with both ferroelectric and suitable band gaps. Recently, the evidence of ferroelectricity in the typical three-dimensional all-inorganic halide perovskites CsGeX3, with band gaps of 1.6 eV to 2.3 eV has been confirmed. However, the spontaneous polarization of ferroelectric perovskite CsGeX3 is ∼10 to 20 μc cm−2 which is weaker than that of ABO3 (∼26 to 75 μc cm−2). Strain engineering has a significant influence on the properties of semiconductor materials by controlling the lattice scaling and the internal atomic spacing. Hence, in this work, strain engineering is introduced to adjust the ferroelectric polarization and the photoelectric properties of ferroelectric perovskite CsGeBr3. The calculated results show that when the applied compressive strain increases from 0% to −4%, the spontaneous polarization of ferroelectric perovskite CsGeBr3 increases from 14.23 μc cm−2 to 51.61 μc cm−2, and the band gap reduces from 2.3631 eV to 1.5310 eV. The effective mass of electrons and holes gradually reduces, exciton binding energies decrease from 48 meV to 5 meV, and the optical absorption coefficient is strongly enhanced from 3 × 105 cm−1 to 5 × 105 cm−1 in the visible range. Besides, the power conversion efficiency(PCE) of CsGeBr3 is significantly increased from 16.95% to 26.77%. Therefore, the results indicate that the application of compressive strain can increase the ferroelectric polarization and enhance the original photovoltaic performance of ferroelectric perovskite CsGeBr3. Our theoretical calculations can provide useful insights and beneficial guidance into experimental studies of ferroelectric perovskites in photoelectric applications.

Gradient gyroid Ti6Al4V scaffolds with TiO2 surface modification: Promising approach for large bone defect repair

Large bone defects, particularly those exceeding the critical size, present a clinical challenge due to the limited regenerative capacity of bone tissue. Traditional treatments like autografts and allografts are constrained by donor availability, immune rejection, and mechanical performance. This study aimed to develop an effective solution by designing gradient gyroid scaffolds with titania (TiO2) surface modification for the repair of large segmental bone defects. The scaffolds were engineered to balance mechanical strength with the necessary internal space to promote new bone formation and nutrient exchange. A gradient design of the scaffold was optimized through Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) simulations to enhance fluid flow and cell adhesion. In vivo studies in rabbits demonstrated that the G@TiO2 scaffold, featuring a gradient structure and TiO2 surface modification, exhibited superior healing capabilities compared to the homogeneous structure and TiO2 surface modification (H@TiO2) and gradient structure (G) scaffolds. At 12 weeks post-operation, in a bone defect representing nearly 30 % of the total length of the radius, the implantation of the G@TiO2 scaffold achieved a 27 % bone volume to tissue volume (BV/TV) ratio, demonstrating excellent osseointegration. The TiO2 surface modification provided photothermal antibacterial effects, enhancing the scaffold's biocompatibility and potential for infection prevention. These findings suggest that the gradient gyroid scaffold with TiO2 surface modification is a promising candidate for treating large segmental bone defects, offering a combination of mechanical strength, bioactivity, and infection resistance.

Matrix models from black hole geometries

Supersymmetric, magnetically charged (and possibly accelerating) black holes in AdS4 that uplift on Sasaki-Einstein manifolds Y7 to M-theory have a dual matrix model description. The matrix model in turn arises by localization of the 3d N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 2 SCFTs, dual to the AdS4 vacuum, on the black hole horizon geometry, which is a Riemann surface Σg (or a spindle Σ). We identify the imaginary part t of the continuously distributed eigenvalues in the matrix model, and their density function ρ(t), with natural geometric quantities associated with the M-theory circle action U(1)M on the near-horizon geometry AdS2 × Y9, the internal space Y9 being a Y7 fibration over Σg (or Σ). Moreover, we argue that the points where ρ′(t) is discontinuous match with the classical action of BPS probe M2-branes wrapping AdS2 and the M-theory circle. We illustrate our findings with the ABJM and ADHM theories, whose duals have Y7 = S7/ℤk, and some of their flavoured variants corresponding to other toric Y7.

INCLUSIVE TECHNIQUES OF COLOR HARMONIZATION OF THE INTERIOR SPACE OF PUBLIC BUILDINGS

The work, based on systematized theoretical and practical experience, defines the main inclusive techniques of color harmonization of the interior space of public buildings in the aspect of comfortable perception of the architectural environment by groups of the population with limited mobility and people with special needs: the technique of using contrasting colors, the technique of using a color coding system, the technique of using Braille and tactile elements, the technique of application of light signals, the technique of using neutral colors for the floor and walls, the technique of using audiovisual signals, the technique of providing touch accessibility, the technique of color indicators of doors and entrance area, the technique of color coding of infrastructure. During the study of inclusive techniques of harmonizing the internal space of public buildings, several aspects that need improvement were identified. The introduction of tactile and sound indicators, effective use of contrasts and a color scheme allowed to create an environment that takes into account the needs of people with visual impairments. For the further development of inclusive spaces, it is recommended to take into account the needs of the community and use the latest research methods. The integration of tactile and sound indicators, the development of multimodal information systems and the application of technological innovations are important elements of increasing the effectiveness of inclusive design.

An experimental and numerical investigation into compressive failure of pyramidal lattice sandwich structures fabricated using stereolithography technology

AbstractThe pyramid lattice sandwich structure, characterized by high load‐bearing capacity, lightweight nature, and fully open internal space, is considered an extremely promising super‐strong structure. Stereolithography technology was utilized to achieve the monolithic formation of single‐layer multi‐cell pyramidal lattice sandwich structures. Quasi‐static compression tests and finite element simulations were conducted to characterize the compressive properties and failure modes. Results indicate that the compressive strength, compressive modulus, specific strength, and specific stiffness of the single‐layer multi‐cell pyramidal lattice sandwich structure increase as the relative density increases. Moreover, fracture failure was observed in the structures with various relative densities. Additionally, the compressive failure of multi‐layer density gradient pyramidal lattice sandwich structures was investigated. Experimental and numerical findings indicate that the optimal density gradient scheme for the ZCMLG structure is I‐III‐II, resulting in a peak compression force that is 342.14% and 288.55% higher than that of the ZAMLG and ZBMLG structures, respectively.

Water Tower Home transformation: bottom-up urban regeneration through a reality TV show

The article examines Wutopia Lab’s transformation of the Water Tower Home (shuita zhijia, also know as ‘House on the House’), a top-floor unit of a residential building converted from a water tower located in a Bulinli lilong neighbourhood in Shanghai. In 2015, the top-floor unit was transformed into a three-bedroom apartment, which was featured in a popular reality TV show Dream Home. Using the concept of ‘raumplan’ as the primary design strategy, the design deploys various heights and platforms to re-organise the internal space while largely maintaining the exterior appearance of the building. It deliberately avoided homogeneous visual control and accommodated the residents’ complex functional requirements within a highly restricted space. The research scrutinises various actors’ involvement during the production of the reality TV show and the transformation process. It highlights how the design team navigated the stakeholders’ complex needs and the rigid yet ambiguous policy related to the regeneration of Shanghai’s unofficial urban heritage. By reflecting upon the various formal and informal design practices in this structure and its eventual demolition, the article illustrates the dilemmas in bottom-up regeneration of the historic urban environment in contemporary China.