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In recent years, the use of dry gas seal technology in high-end industrial applications has become increasingly widespread. Existing research has primarily focused on unidirectional grooves. This study introduces an innovative approach by incorporating bidirectional grooves inspired by the biomimetic design of a carp tail, aiming to enhance sealing performance. The analysis of flow-field characteristics was conducted using Fluent software to evaluate the effect of different groove designs on sealing efficacy. The results indicate that curved grooves are more effective in directing gas flow and reducing fluid dynamic losses, thus improving the overall sealing efficiency. In particular, the outer-curved carp-tail groove exhibited superior dynamic pressure effects and reduced pressure drops across various operating conditions. The optimal radial dam-to-groove width ratio ranged from 3.8 to 4.1, and the optimal groove depth ranged from 6.5 to 9.6 μm. This investigation focused on the design and performance evaluation of biomimetic carp-tail grooves for dry gas seals, presenting a novel groove configuration for end-face sealing and further advancing the theoretical understanding of dry gas seals. [ABSTRACT FROM AUTHOR]

In order to solve the problems of the nuclear accident emergency drill, such as invisible radiation field, potential radiation risk, and high labor costs, therefore, an adaptive ray-casting 3D nuclear radiation field visualization method based on feature importance was developed in this study. The nuclear accident emergency disposal drill training simulation system was developed based on the Unity3D simulation engine. The 3D visualization of a nuclear radiation field with millions of grids was realized using ShaderLab programming. Multi-job personnel collaborative operation exercise simulation was realized based on the finite state machine. The system frame rate was approximately 60 frames, which meets real-time interaction requirements. Considering an out-of-control radioactive source accident as a case, the operation modes and emergency disposal processes of the nuclear accident emergency drill could be rebuilt by the system. The proposed solution of the simulation system could be applied to ensure personnel radiation safety, enrich training methods, and reduce training costs.

A simple sol-gel method has been utilized to synthesize MAl2O4:Cr catalysts (M = Mg, Co, Zn). The spinel-type MAl1.9Cr0.1O4 was formed after Cr ions were introduced into MAl2O4, as confirmed by various characterization methods. The particle size of MAl2O4:Cr catalyst increases with the increasing of the M ion radius, and CoAl2O4:Cr catalyst has the highest uniformity with an average particle size of 60 nm. The CoAl2O4:Cr catalyst is effective in degrading oil and gas field wastewater through the combination of ultrasonic and simulated solar irradiation and has a high visible light absorption coefficient. The CoAl2O4:Cr catalyst has high cyclic stability, and its optimal catalyst content is 0.5 g/L. Capture experiment and possible mechanism analysis confirm that the electrons, holes, hydroxyl radicals and superoxide radicals are the main active species in CoAl2O4:Cr catalyst for the degradation of oil and gas field wastewater. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene/aluminum (PTFE/Al) reactive material is a pivotal research object in the aerospace, military, and mechanical engineering fields and can release chemical energy (CE) under shock or impact. However, its relatively low mechanical strength limits its applications. The present paper proposes a Cu-PTFE/Al (73.5wt. %/26.5wt. %) double-layer liner that can form tandem explosive formed projectiles (EFPs) under the shock of shaped charges, which not only retains the strong penetration ability but also shows a more significant lateral enhancement effect through the deflagration reaction. Here, the preparation process of the PTFE/Al liner is given, and an analytical model for the Cu-PTFE/Al tandem EFP of the damage process against multi-spaced plates is established, revealing the penetration and deflagration-enhanced mechanisms. Subsequently, a two-step segmented numerical simulation for the penetration–deflagration coupling effects is conducted, and the time-space interaction process and damage results between kinetic energy penetration and CE deflagration are obtained. A series of experiments of tandem EFPs against spaced plates are conducted, including the different materials, thickness ratio, and standoff. Experimental results show that compared with Cu–Cu tandem EFP with the same condition, the penetration ability of Cu-PTFE/Al composite EFP is reduced, but the damage enhancement effect is greatly improved; the maximum damage area of a single plate is increased by 220.1%, and the average damage area of a single plate is increased by 76.2%. This study provides important reference data and a theoretical basis for the design of metal-reactive tandem EFPs. [ABSTRACT FROM AUTHOR]

A well-known theorem by Chvátal-Erdőos [A note on Hamilton circuits, Discrete Math. 2 (1972) 111–135] states that if the independence number of a graph G is at most its connectivity plus one, then G is traceable. In this article, we show that every 2-connected claw-free graph with independence number α(G) ≤ 6 is traceable or belongs to two exceptional families of well-defined graphs. As a corollary, we also show that every 2-connected claw-free graph with independence number α(G) ≤ 5 is traceable.

Let r≥2 $r\ge 2$ and let F $F$ be an (r+1) $(r+1)$ ‐chromatic graph with a color‐critical edge, that is, there exists e∈E(F) $e\in E(F)$ such that F−e $F-e$ has chromatic number r $r$. Gerbner recently conjectured that every n $n$ ‐vertex maximal F $F$ ‐free graph with at least (1−1r)n22−o(nr+1r) $(1-\frac{1}{r})\frac{{n}^{2}}{2}-o({n}^{\frac{r+1}{r}})$ edges contains an induced complete r $r$ ‐partite graph on n−o(n) $n-o(n)$ vertices. Let Fs,k ${F}_{s,k}$ be a graph obtained from s $s$ copies of C2k+1 ${C}_{2k+1}$ by sharing a common edge. In this paper, we show that for all k≥2 $k\ge 2$ if G $G$ is an n $n$ ‐vertex maximal Fs,k ${F}_{s,k}$ ‐free graph with at least n2∕4−o(ns+2s+1) ${n}^{2}\unicode{x02215}4-o({n}^{\frac{s+2}{s+1}})$ edges, then G $G$ contains an induced complete bipartite graph on n−o(n) $n-o(n)$ vertices. We also construct graphs to show that the magnitude in o(ns+2s+1) $o({n}^{\frac{s+2}{s+1}})$ is best possible, which disproves Gerbner's conjecture for r=2 $r=2$. [ABSTRACT FROM AUTHOR]

We performed two‐dimensional simulations of the slicing of a rising droplet by a vertical knife and by two knives. We used a free‐energy lattice Boltzmann method. Most simulations are for an Eötvös number of 3.96 and a Morton number of 1.24 × 10−4. We carefully probed effects of the spatial resolution on the rising speed and slicing process. The effect of wettability of the knife(s) was studied by varying the equilibrium contact angle of the drop on the knife in the range of 45° to 135°. Slicing time as well as fine droplet fragments staying behind on the knife depend on the knife's wettability. [ABSTRACT FROM AUTHOR]

Objective To summarize the incidence, clinical manifestations, diagnosis and treatment of basal cell ne⁃ vus syndrome and to provide reference for clinical diagnosis and treatment. Methods Retrospective analysis of 4 cas⁃ es of basal cell nevus syndrome admitted to the General Hospital of PLA during January 2017 to January 2018 and re⁃ cent cases reported in the literature. Results In this study, 1 males and 3 females were included. The patients includ⁃ ed a mother and her child. All 4 cases were surgically resected. Pathological reports included all keratocysts of the jaws. There has been no recurrence since follow⁃up. Through literature summarization and analysis, the clinical manifesta⁃ tions of this syndrome were found to be diverse. Typical clinical manifestations include multiple keratocysts of the jaws, multiple blepharospasms or cancers, deformities of the spine or ribs, increased brachial distance, eye diseases or special face intracranial calcification. Conclusion Basal cell nevus syndrome is an autosomal dominant genetic disorder. The clinical manifestations are diverse and the diagnosis is often overlooked. The incidence of cysts in the jaws is one of the important clinical manifestations of this syndrome. Early diagnosis and proper treatment improve patient survival and quality of life.

The use of high‐power circuit devices puts forward high heat dissipation requirements for LED display. Several heat dissipation methods are studied in this paper to provide a reasonable idea of high power consumption LED display. [ABSTRACT FROM AUTHOR]

Single-nanoparticle detection has received tremendous interest due to its significance in fundamental physics and biological applications. Here, we demonstrate an optical nanofibre-enabled microfluidic sensor for the detection and sizing of nanoparticles. Benefitting from the strong evanescent field outside the nanofibre, a nanoparticle close to the nanofibre can scatter a portion of the field energy to the environment, resulting in a decrease in the transmitted intensity of the nanofibre. On the other hand, the narrow and shallow microfluidic channel provides a femtoliter-scale detection region, making nanoparticles flow through the detection region one by one. By real-time monitoring of the transmitted intensity of the nanofibre, the detection of a single polystyrene (PS) nanoparticle as small as 100 nm in diameter and exosomes in solution is realised. Based on a statistical analysis, the mean scattering signal is related to the size of the nanoparticle. Experimentally, a mixture of nanoparticles of different diameters (200, 500, and 1000 nm) in solution is identified. To demonstrate its potential in biological applications, high-throughput counting of yeasts using a pair of microchannels and dual-wavelength detection of fluorescently labelled nanoparticles are realised. We believe that the developed nanoparticle sensor holds great potential for the multiplexed and rapid sensing of diverse viruses. [ABSTRACT FROM AUTHOR]

Asymmetric supercapacitors (ASCs) with flexible performance have considerable potential for applications in wearable and implantable electronics; however, traditional electrodes have low energy intensity and fragility, which makes meeting the increasing requirements of green energy supply devices challenging. In this study, a recyclable Fe3O4/multiwalled carbon nanotube (MWCNT)/cellulose nanofiber (CNF) nanopaper was constructed based on a three-dimensional conductive network between MWCNT@Fe3O4 and CNFs using simple vacuum filtration technology. As the negative electrode, the nanopaper exhibits exceptional flexibility (it can be folded into a small plane without breaking), high electrical conductivity (1016.3 S m−1), and extraordinary mass- and volume-specific capacitances of 229.9 F g−1 and 735.68 mF cm−2 at 5 mV s−1, respectively. A flexible ASC comprising Fe3O4/MWCNT/CNF demonstrated a high specific capacity of 107.0 F g−1 (2.94 F cm−2) at a current density of 0.5 A g−1. It exhibited an energy density and a power density of 38.0 W h kg−1 and 405.1 W kg−1, respectively. Furthermore, the capacitor retained an energy density of 18.8 W h kg−1 at a high power density (42.2 kW kg−1) and >90% of the specific capacitance after 5000 charge–discharge cycles at 5 A g−1. This research will pave the way for further advances in degradable and recyclable nanopaper electrodes toward building a cutting-edge multifunctional platform for electronic skin, human motion recording, and wearable electronics. [ABSTRACT FROM AUTHOR]