To clarify the combustion process of a modular charge system with a primer gap, the rules governing the cartridge movement and pressure change in the chamber are analyzed. Based on the ...characteristics of the modular charge system, an axisymmetric two-phase flow model of the interior ballistics is established, with the monotonic upward-centered scheme for conservation laws adopted to calculate the combustion process. Compared with the experimental results, the difference in the peak pressure is less than 5%, which indicates that the mathematical model and scheme are reliable and accurate. The results show that, during the initial stage of ignition, the combustible container remains unbroken, and the gas and solid particles are prevented from spreading to the chamber by the end cap of the cartridge. Thus, only the gas inside the igniter tube influences the flow field in the chamber. After the combustible container has broken, the gas and solid particles move rapidly toward the cavity from the combustible container. The axial movement of solid particles is more intense than that of the gas particles, but the radial movement of solid particles is relatively weak. Furthermore, the existence of the primer gap leads to a delay in the ignition time of the solid particles, which delays the rupture time of the igniter tube and the module cartridge.
Abstract
Single-atom catalysts show excellent catalytic performance because of their coordination environments and electronic configurations. However, controllable regulation of single-atom ...permutations still faces challenges. Herein, we demonstrate that a polarization electric field regulates single atom permutations and forms periodic one-dimensional Au single-atom arrays on ferroelectric Bi
4
Ti
3
O
12
nanosheets. The Au single-atom arrays greatly lower the Gibbs free energy for CO
2
conversion via Au-O=C=O-Au dual-site adsorption compared to that for Au-O=C=O single-site adsorption on Au isolated single atoms. Additionally, the Au single-atom arrays suppress the depolarization of Bi
4
Ti
3
O
12
, so it maintains a stronger driving force for separation and transfer of photogenerated charges. Thus, Bi
4
Ti
3
O
12
with Au single-atom arrays exhibit an efficient CO production rate of 34.15 µmol·g
−1
·h
−1
, ∼18 times higher than that of pristine Bi
4
Ti
3
O
12
. More importantly, the polarization electric field proves to be a general tactic for the syntheses of one-dimensional Pt, Ag, Fe, Co and Ni single-atom arrays on the Bi
4
Ti
3
O
12
surface.
Aqueous supercapacitors have occupied a significant position among various types of stationary energy storage equipment, while their widespread application is hindered by the relatively low energy ...density. Herein, N/F co-doped carbon materials activated by manganese clusters (NCM) are constructed by the straightforward experimental routine. Benefiting from the elevated conductivity structure at the microscopic level, the optimized NCM-0.5 electrodes exhibited a remarkable specific capacitance of 653 F g
at 0.4 A g
and exceptional cycling stability (97.39% capacity retention even after 40,000 cycles at the scanning rate of 100 mV s
) in a neutral 5 M LiCl electrolyte. Moreover, we assembled an asymmetric device pairing with a VO
anode (NCM-0.5//VO
), which delivered a durable life span of 95% capacity retention over 30,000 cycles and an impressive energy density of 77.9 Wh kg
. This study provides inspiration for transition metal element doping engineering in high-energy storage equipment.
Acute mesenteric ischemia is a rare but lethal disease. Acute occlusive mesenteric ischemia consists of mesenteric artery embolism, mesenteric artery thrombosis, and mesenteric vein thrombosis. This ...study aimed to investigate the factors that may affect the outcome of acute occlusive mesenteric ischemia.
Data from acute occlusive mesenteric ischemia patients admitted between May 2016 and May 2022 were reviewed retrospectively. Patients were divided into 2 groups according to whether complications(Clavien‒Dindo ≥ 2) occurred within 6 months of the first admission. Demographics, symptoms, signs, laboratory results, computed tomography angiography features, management and outcomes were analyzed.
59 patients were enrolled in this study. Complications(Clavien‒Dindo ≥ 2) occurred within 6 months of the first admission in 17 patients. Transmural intestinal necrosis, peritonitis, white blood cell count, percentage of neutrophils, percentage of lymphocytes, neutrophil-to-lymphocyte ratio, lactate dehydrogenase, creatine kinase isoenzyme, cardiac troponin I, laparoscopic exploration rate, open embolectomy rate, enterostomy rate, length of necrotic small bowel, length of healthy small bowel, surgical time and intraoperative blood loss differed significantly between groups. Creatine kinase isoenzyme (OR = 1.415, 95% CI: 1.060-1.888) and surgical time (OR = 1.014, 95% CI: 1.001-1.026) were independent risk factors associated with complications(Clavien‒Dindo ≥ 2).
Our analysis suggests that acute occlusive mesenteric ischemia patients with a creatine kinase isoenzyme level greater than 2.22 ng/mL or a surgical time longer than 156 min are more likely to experience complications'(Clavien‒Dindo ≥ 2) occurrence within 6 months of the first admission.
Electrochemical synthesis of ammonia has the advantages of low energy consumption and promising environmental protection, as compared to the traditional Haber-Bosch process. However, the commercial ...utilization of this novel system is limited by the low Faradaic efficiency, poor ammonia yield and high overpotential due to the strong NN bond and the dominant competing reaction of hydrogen evolution reaction (HER). Herein, a BiOCl-modified two-dimensional (2D) titanium carbide MXenes nanocomposite (BiOCl@Ti3C2Tx) is proposed as a promising electrocatalyst for ambient nitrogen (N2) reduction reaction with excellent catalytic performance and superior long-term stability at low overpotential. In 0.1 mol/L HCl, this catalyst attains a high Faradic efficiency of 11.98% and a NH3 yield of 4.06 µg h−1 cm−2 at −0.10 V (vs. RHE), benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, combined with its large specific surface area and the facile electron transfer.
Display omitted A noble-metal free electrocatalytic system of BiOCl@Ti3C2Tx has been fabricated via in-situ hydrothermal growth of BiOCl on the Ti3C2Tx, showing significantly enhanced electrocatalytic nitrogen reduction reaction performance at low overpotential.
Highlights
Molybdenum aluminum boride single crystals as layered ternary borides were firstly applied for the electrochemical N
2
reduction reaction under ambient conditions and in alkaline media, ...displaying excellent electrocatalytic performances at the low overpotential.
Through the combination of the strong interaction of Al/B band and N orbitals and the special crystal structure exposing more active sites, synergistic effect of the elements was verified to achieve the enhancement of N
2
reduction reaction process and the limitation of hydrogen evolution reaction.
Achieving more meaningful N
2
conversion by reducing the energy input and carbon footprint is now being investigated through a method of N
2
fixation instead of the Haber–Bosch process. Unfortunately, the electrochemical N
2
reduction reaction (NRR) method as a rising approach currently still shows low selectivity (Faradaic efficiency < 10%) and high-energy consumption applied potential at least − 0.2 V versus the reversible hydrogen electrode (RHE). Here, the role of molybdenum aluminum boride single crystals, belonging to a family of ternary transition metal aluminum borides known as MAB phases, is reported for the electrochemical NRR for the first time, at a low applied potential (− 0.05 V versus RHE) under ambient conditions and in alkaline media. Due to the unique nano-laminated crystal structure of the MAB phase, these inexpensive materials have been found to exhibit excellent electrocatalytic performances (NH
3
yield: 9.2 µg h
−1
cm
−2
mg
cat.
−1
, Faradaic efficiency: 30.1%) at the low overpotential, and to display a high chemical stability and sustained catalytic performance. In conjunction, further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N
2
due to the strong interaction between the B 2
p
/Al 3
p
band and the N 2
p
orbitals, while Mo exhibits specific catalytic activity toward the subsequent reduction reaction. Overall, the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance. The significance of this work is to provide a promising candidate in the future synthesis of ammonia.
High salt intake is a major risk factor for hypertension and is associated with cardiovascular events. Most countries exhibit a traditionally high salt intake; thus, identification of an optimal ...strategy for salt reduction at the population level may have a major impact on public health. In this multicenter, random-order, double-blind observational and interventional study, subjects with a high spice preference had a lower salt intake and blood pressure than subjects who disliked spicy food. The enjoyment of spicy flavor enhanced salt sensitivity and reduced salt preference. Salt intake and salt preference were related to the regional metabolic activity in the insula and orbitofrontal cortex (OFC) of participants. Administration of capsaicin-the major spicy component of chili pepper-enhanced the insula and OFC metabolic activity in response to high-salt stimuli, which reversed the salt intensity-dependent differences in the metabolism of the insula and OFC. In animal study, OFC activity was closely associated with salt preference, and salty-taste information processed in the OFC was affected in the presence of capsaicin. Thus, interventions related to this region may alter the salt preference in mice through fiber fluorometry and optogenetic techniques. In conclusion, enjoyment of spicy foods may significantly reduce individual salt preference, daily salt intake, and blood pressure by modifying the neural processing of salty taste in the brain. Application of spicy flavor may be a promising behavioral intervention for reducing high salt intake and blood pressure.
In the viewpoint of ammonia economy, electrochemical N2 reduction reaction (NRR) under mild condition is a very promising approach for sustainable development. By virtue of robust activity and low ...cost, transition-metal-based materials become one kind of the most attractive electrocatalysts in realizing ammonia synthesis to the industrial level. However, the investigation related to NRR electrocatalysts still mainly rely on costly substance or fabrication process, which greatly restrict their large-scale applications. In this work, a simple fabricated FeS2 electrode is adopted as NRR catalysts. The abundant surface defects due to the existence of Cr element, as well as the synergistic effect between FeS2 crystal planes provided excellent electrocatalytic performance with a high NH3 yield rate (11.5 μg h−1mg -1Fe) and Faradaic efficiency (14.6%) at -0.2 V vs. reversible hydrogen electrode (RHE) toward NRR under ambient conditions. The superior catalytic performance of such non-precious metal catalysts would strongly promote the application of NRR process industrially.
Low temperatures pose a significant threat to plant growth and development. Studies have shown that aquaporins (AQPs), as the main functional proteins on the cell membrane regulating water ingress ...and egress, play a vital role in maintaining dynamic water balance when plants face cold stress. Catalpa bungei, an important timber and ornamental tree species, has its cultivation range significantly limited by its poor cold tolerance. However, no study has been found aiming to identify its aquaporin gene family. This study aims to fill this gap using two C. bungei cultivars with differing cold tolerance as experimental material: “Qiuza 1”, which is less cold-tolerant, and “Qiuza 2”, which is more cold-tolerant. The plants were subjected to low-temperature stress at 4 °C for 24 h. Using high-throughput molecular sequencing technology, a transcriptome sequencing of the leaves was performed at 0, 6, 12, and 18 h of cold stress. Fifteen candidate aquaporin genes in C. bungei (CbAQP) were identified. Phylogenetic analysis showed that the CbAQP gene family is divided into five subfamilies: 5 PIPs, 4 TIPs, 3 NIPs, 2 SIPs, and 1 XIP. By analyzing AQPs related to cold stress in other plants and the expression patterns of CbAQP genes, 12 CbAQP genes related to cold stress were identified. The genes that responded positively include CbPIP2;5, CbPIP1;2, CbTIP4;1, and CbNIP2;1. The results provide a foundation for further analysis of the biological functions of candidate CbAQP genes related to cold tolerance and offer theoretical support for improving seedling quality, cold-resistant genetic breeding, and expanding its distribution range.
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