Lattice Boltzmann flux solver for simulation of hypersonic flows

In this paper, a stable Lattice Boltzmann Flux Solver (LBFS) is proposed for simulation of hypersonic flows. In LBFS, the finite volume method is applied to solve the Navier-Stokes equations. One-dimensional Lattice Boltzmann model is applied to reconstruct the inviscid flux across the cell interface, while the viscous flux is solved by conventional smooth approximation function. The present work extends the existing LBFS to calculate hypersonic flow field on the leeward, which is hard to get convergent results due to extremely low pressure effects in this area. Simulation of a biconics model is studied. It is discovered that the tail area of double cone is related to the maximum Mach number that could be convergent. The larger the diameter of tail area is, the smaller Mach number could be convergent. Hence, the low pressure area behind double cone tail will have large effects during the LBFS simulation of hypersonic flow. Two measurements are applied in this paper to overcome the low pressure problem. The first one is to apply a local block grid refinement method based on the flow conditions for improving the stability. The second is to add a constraint parameter to eliminate negative value and give out a proper one. Hence, LBFS is able to get convergent result of the hypersonic flow field on both windward and leeward. Several numerical examples are tested to compare the performance of method presented in this paper. Simulation results show that method present in this paper is able to calculate hypersonic flow field on the leeward with both fine accurate and efficient

Interprovincial reliance for improving air quality in China:A case study on black carbon aerosol

Black carbon (BC) is of global concern because of its adverse effects on climate and human health. It can travel long distances via atmospheric movement and can be geographically relocated through trade. Here, we explored the integrated patterns of BC transport within 30 provinces in China from the perspective of meteorology and interprovincial trade using the Weather Research and Forecasting with Chemistry (WRF/Chem) model and multiregional input-output analysis. In general, cross-border BC transport, which accounts for more than 30% of the surface concentration, occurs mainly between neighboring provinces. Specifically, Hebei contributes 1.2 μg·m(-3) BC concentration in Tianjin. By contrast, trade typically drives virtual BC flows from developed provinces to heavily industrial provinces, with the largest net flow from Beijing to Hebei (4.2 Gg). Shanghai is most vulnerable to domestic consumption with an average interprovincial consumption influence efficiency of 1.5 × 10(-4) (μg·m(-3))/(billion Yuan·yr(-1)). High efficiencies (∼8 × 10(-5) (μg·m(-3))/(billion Yuan·yr(-1))) are also found from regions including Beijing, Jiangsu, and Shanghai to regions including Hebei, Shandong, and Henan. The above source-receptor relationship indicates two control zones: Huabei and Huadong. Both mitigating end-of-pipe emissions and rationalizing the demand for pollution-intense products are important within the two control zones to reduce BC and other pollutants

Picosecond electric-field-induced threshold switching in phase-change materials

Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag$_4$In$_3$Sb$_{67}$Te$_{26}$. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on sub-picosecond time-scales - faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.Comment: 6 pages manuscript with 3 figures and 8 pages supplementary materia

Developments in synthesis, characterization, and application of large, high-quality CVD single crystal diamond

Single crystal diamond synthesis by microwave plasma chemical vapor deposition at rapid growth rate has considerably advanced in the past few years. Developments have been made in growth, optical quality, and mechanical properties. Of the various types of single crystal diamond that can be produced using these techniques, high quality single crystal CVD diamond can be routinely produced, and this material is playing an increasing role in research on materials under extreme conditions. This article highlights recent developments in single crystal CVD diamond synthesis and characterization, as well as various applications in high-pressure materials research.За останні кілька роки синтез монокристалів алмазу мікрохвильовим плазмовим хімічним осадженням з газової фази з високою швидкістю значно просунувся. Прогрес було досягнуто у рості, оптичних і механічних властивостях. З різних типів монокристалічного алмазу, що можна отримати з використанням цього методу, регулярно виробляють високоякісні монокристалічні CVD-алмази, і цей матеріал відіграє все більш важливу роль при дослідженні матеріалів в екстремальних умовах. У даній роботі висвітлено останні досягнення в синтезі монокристалічного CVD-алмазу і дослідженні його характеристик, а також його різне застосування у дослідженні матеріалів при високому тиску.За последние несколько лет синтез монокристаллов алмаза микроволновым плазменным химическим осаждением из газовой фазы с высокой скоростью значительно продвинулся. Прогресс был достигнут в росте, оптических и механических свойствах. Из различных типов монокристаллического алмаза, которые могут быть получены с использованием этого метода, регулярно производят высококачественные монокристаллы CVD-алмаза, и этот материал играет все более важную роль в исследовании материалов в экстремальных условиях. В этой работе осветлены последние разработки в синтезе монокристаллов CVD-алмаза и исследовании его характерист

Bifidobacterium bifidum BB28 microencapsulated with ca-alginate: Survival under simulated gastrointestinal conditions and stability during storage

The present study was to evaluate the survival rate of free and encapsulated Bifidobacterium bifidum BB28 under simulated gastrointestinal conditions and its stability during storage. Results showed that non-microencapsulated Bifidobacterium bifidum BB28 was more susceptible to simulated gastrointestinal conditions than microencapsulated bacteria. Microencapsulated Bifidobacterium BB28 exhibited a lower population reduction than free cells during exposure to simulated gastrointestinal conditions, the viable count of monolayer microcapsules, double layer microcapsules, and triple layer microcapsules decreased by nine magnitudes, four magnitudes, and one magnitude after 2 h, respectively. The enteric test showed that the microorganism cells were released from the monolayer, double layer, and triple layer microcapsules completely in 40 min. Moreover, the optimum storage times of free Bifidobacterium BB28, monolayer microcapsules, double layer microcapsules, and triple layer microcapsules were 21 days, 21 days, 28 days, and more than 35 days in orange juice, pure milk, and nutrition Express (a commercially available milk based drink), and the viable counts were maintained at 1×106 CFU g−1 or more, which means that the double layer and triple layer of microcapsules of B. bifidum BB28 have great potential in food application

Phase segregation in NaxCoO2 for large Na contents

We have investigated a set of sodium cobaltates (NaxCoO2) samples with various sodium content (0.67 \le x \le 0.75) using Nuclear Quadrupole Resonance (NQR). The four different stable phases and an intermediate one have been recognized. The NQR spectra of 59Co allowed us to clearly differentiate the pure phase samples which could be easily distinguished from multi-phase samples. Moreover, we have found that keeping samples at room temperature in contact with humid air leads to destruction of the phase purity and loss of sodium content. The high sodium content sample evolves progressively into a mixture of the detected stable phases until it reaches the x=2/3 composition which appears to be the most stable phase in this part of phase diagram.Comment: 5 pages, 4 figure

Probing flavor changing interactions in photon-photon collisions

We examine the subprocess $\gamma\gamma \to t\bar{c}+\bar{t}c$ at electron-positron colliders in the two-Higgs-doublet model with flavor-changing scalar couplings, where all the one-loop contribuions are considered, and the results are applicable to the whole mass range of the weakly coupled Higgs bosons. Because of the heavy top quark mass, this process is important in probing the flavor-changing top-charm-scalar vertex and could be detectable at the Next Linear Collider, if the values of the parameters are favorable. The results show that this process is more promising than the direct $e^{+} e^{-}$ process for discovering flavor changing scalar interactions.Comment: 22 pages, LaTeX, including 5 figures in eps file

An Updated Search of Steady TeV γ−\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV $\gamma-$ray point sources has now been updated by a factor of 2.8 improved statistics. From $0.0^{\circ}$ to $60.0^{\circ}$ in declination (Dec) range, no new TeV $\gamma-$ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV $\gamma-$ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn

Pangolin genomes offer key insights and resources for the world's most trafficked wild mammals

DATA AVAILABILITY : Draft genomes (Manis culionensis, M. crassicaudata, Phataginus tetradactyla, Smutsia temminckii) and the hybrid assembled, annotated reference genome with associated metadata (S. gigantea) are available in the GenBank Nucleotide Database (BioProject: PRJNA795390). The associated sequence read data have also been deposited in Genbank (SRA: SRR17702824-SRR17702828) for the aforementioned genomes (except for S. temminckii). The accession numbers or links for all accessed genomic data are listed in supplementary table S1, Supplementary Material online. A database containing the list genes ranked by diversity amongst all eight pangolin species has been deposited at Zenodo and is publicly available (supplementary Database S1, Supplementary Material online: https://doi.org/10.5281/zenodo.7517409). All original code in the form of custom scripts for processing the genomics data in this study have also been deposited at Zenodo and are publicly available (Custom scripts 1–3: https://doi.org/10.5281/zenodo.7517409). Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.Pangolins form a group of scaly mammals that are trafficked at record numbers for their meat and purported medicinal properties. Despite their conservation concern, knowledge of their evolution is limited by a paucity of genomic data. We aim to produce exhaustive genomic resources that include 3,238 orthologous genes and whole-genome polymorphisms to assess the evolution of all eight extant pangolin species. Robust orthologous gene-based phylogenies recovered the monophyly of the three genera and highlighted the existence of an undescribed species closely related to Southeast Asian pangolins. Signatures of middle Miocene admixture between an extinct, possibly European, lineage and the ancestor of Southeast Asian pangolins, provide new insights into the early evolutionary history of the group. Demographic trajectories and genome-wide heterozygosity estimates revealed contrasts between continental versus island populations and species lineages, suggesting that conservation planning should consider intraspecific patterns. With the expected loss of genomic diversity from recent, extensive trafficking not yet realized in pangolins, we recommend that populations be genetically surveyed to anticipate any deleterious impact of the illegal trade. Finally, we produce a complete set of genomic resources that will be integral for future conservation management and forensic endeavors for pangolins, including tracing their illegal trade. These comprise the completion of whole-genomes for pangolins through the hybrid assembly of the first reference genome for the giant pangolin (Smutsia gigantea) and new draft genomes (∼43x–77x) for four additional species, as well as a database of orthologous genes with over 3.4 million polymorphic sites.The Agence Nationale de la Recherche, European Research Council, Mohamed bin Zayed Species Conservation Fund, the National Research Foundation of South Africa and the National Natural Science Foundation of China.https://academic.oup.com/mbehj2024Mammal Research InstituteZoology and EntomologySDG-15:Life on lan

Genome wide analysis of gene expression changes in skin from patients with type 2 diabetes

Non-healing chronic ulcers are a serious complication of diabetes and are a major healthcare problem. While a host of treatments have been explored to heal or prevent these ulcers from forming, these treatments have not been found to be consistently effective in clinical trials. An understanding of the changes in gene expression in the skin of diabetic patients may provide insight into the processes and mechanisms that precede the formation of non-healing ulcers. In this study, we investigated genome wide changes in gene expression in skin between patients with type 2 diabetes and non-diabetic patients using next generation sequencing. We compared the gene expression in skin samples taken from 27 patients (13 with type 2 diabetes and 14 non-diabetic). This information may be useful in identifying the causal factors and potential therapeutic targets for the prevention and treatment of diabetic related diseases