Fish oil omega-3 Fatty Acids Alleviate Postoperative delirium-like Behavior in aged mice by Attenuating Neuroinflammation and Oxidative Stress.

Postoperative delirium (POD) is a common and serious neuropsychiatric syndrome among older patients, and lacks effective therapies. Omega-3 fatty acids, possessing anti-inflammatory and antioxidant properties, have shown potent neuroprotective effects in several diseases. The present study investigated whether omega-3 fatty acids could exert a neuroprotective role against POD in aged mice. A mouse model of POD was established to explore the role of omega-3 fatty acids in laparotomy-induced delirium-like behavior by evaluating systemic inflammatory changes, neuroinflammation, oxidative stress, and behavior at different time points in aged mice. Oral gavage with omega-3 fatty acids (300 mg/kg) for 3 weeks before surgery significantly attenuated anesthesia/surgery-induced POD-like behavior and the accumulation of proinflammatory cytokines from the peripheral blood in aged mice. Moreover, it also remarkably mitigated neuroinflammation and the oxidative stress response (malondialdehyde [MDA] and superoxide dismutase [SOD]) in the prefrontal cortex and hippocampus of surgical mice. Our findings provided evidence that pretreatment with omega-3 fatty acids may play a vital role in the treatment of POD through mechanisms involving its anti-inflammatory and antioxidant effects, which may be a promising prevention strategy for POD in aged patients.

Multi-scale failure mechanisms of hydraulic engineering exposed to seasonally frozen salinization environment: Integrating SBAS-InSAR and mechanical experiments.

Constructing hydraulic engineering ensures agricultural development and improves salinization environments. However, in seasonally frozen salinization regions, hydraulic engineering is prone to deformation failure. Leakage from canal raises the regional groundwater level, triggering secondary salinization environmental issues. Exploring the instability mechanisms is thus necessary for hydraulic engineering. Traditional deformation monitoring techniques and soil experiments are constrained by observation scale and timeliness. In this study, Sentinel-1B data from November 2017 to August 2019 were acquired. The small baseline subset (SBAS) InSAR approach was employed to interpret the seasonal deformation characteristics in both the vertical and slope directions of a damaged canal segment in Songyuan, Northeast China. The mechanical properties of saline-alkali soil under varying water contents were quantified by integrating unconfined compression experiment (UCE). In May, as the soil thawed downward, a frozen lenses with poor permeability formed at a depth of approximately 100 cm, causing the accumulation of meltwater and infiltrated precipitation between the frozen layer and the melting layer in the canal. The soil water content at a depth of 80 to 140 cm exceeded 22 %, reaching a threshold for rapid reduction in unconfined compression strength (UCS). Consequently, in spring, the low soil strength between the frozen layer and the melting layer resulted in interface sliding, with a displacement of -133.88 mm in the canal slope direction. Furthermore, the differential projection of freeze-thaw deformation in the slope direction caused continuous creep of the canal towards the free face, with a value of -23.27 mm, exacerbating the formation of the late spring landslide. Integrating InSAR and engineering geological analysis is beneficial for addressing deformation issues in hydraulic engineering. Ensuring the sustainable operation of hydraulic engineering holds important implications for mitigating the salinization process.

Preparation and Photocatalytic Degradation Performance of Amine-Rich Carbon Nitride with Structural Modulation of the Precursor.

The photocatalytic performance of graphitic phase carbon nitride (g-C3N4) is strongly influenced by its own microstructure as well as the precursor structure that causes the microstructure changes. In this paper, a composite precursor of sodium chloride and cyanamide (NaCl/CA-2) was obtained by freeze-drying, which possess an aggregated state different from that of the non-freeze-drying method. This new aggregation state with the introduction of sodium ions into the cyanamide lattice results in a higher activation energy of NaCl/CA-2 in the thermal polycondensation process of the molten salt-assisted preparation of g-C3N4, which prevented the condensation of two cyanamides to one dicyandiamide, ultimately obtaining FD-CN with an amino-rich structure. The nitrogen atoms on the amino group can provide the photocatalyst with more unpaired electrons that can participate in the photoexcitation process, further improving its electron-hole separation ability and charge transfer efficiency, thus effectively enhancing its photocatalytic activity. Compared to the original g-C3N4, the photocatalytic activity of FD-CN for the degradation of methylene blue increased 2.19 times.

Investigation on the Effect of Calcium on the Properties of Geopolymer Prepared from Uncalcined Coal Gangue.

In this paper, the influence of calcium on coal gangue and fly ash geopolymer is explored, and the problem of low utilization of unburned coal gangue is analyzed and solved. The experiment took uncalcined coal gangue and fly ash as raw materials, and a regression model was developed with the response surface methodology. The independent variables were the CG content, alkali activator concentration, and Ca(OH)2 to NaOH ratio (CH/SH). The response target value was the coal gangue and fly-ash geopolymer compressive strength. The compressive strength tests and the regression model obtained by the response surface methodology showed that the coal gangue and fly ash geopolymer prepared with the content of uncalcined coal gangue is 30%, alkali activator content of 15%, and the value of CH/SH is 1.727 had a dense structure and better performance. The microscopic results demonstrated that the uncalcined coal gangue structure is destroyed under an alkali activator's action, and a dense microstructure is formed based on C(N)-A-S-H and C-S-H gel, which provides a reasonable basis for the preparation of geopolymers from the uncalcined coal gangue.

A Randomized Controlled Trial: Examining the Impact of the Novel Double Setup Endotracheal Tube on the Success Rates of Awake Fiber-Optic Orotracheal Intubation.

BACKGROUND: Advancing the endotracheal tube (ETT) over a flexible bronchoscope (FB) during awake fiber-optic intubation (AFOI) is often impeded. Various maneuvers and tracheal tubes designed to overcome this obstruction may also be unsuccessful or costly. OBJECTIVE: The current study aimed to assess how the novel double configuration ETT affected AFOI success rates on the first attempt. METHODS: A randomized controlled experiment including 40 individuals receiving awake fiber-optic orotracheal intubation was performed in a 1:1 ratio with a single ETT railroaded with its bevel posteriorly (ST) or railroading with a double setup ETT (DT) over a flexible videoscope (FVS) for tracheal intubation. The number of intubation attempts, time spent intubating, and adverse events were examined and compared between the two groups. RESULTS: Twenty patients received a single ETT railroaded with the bevel posteriorly, and 20 patients received railroading with the double setup ETT during AFOI. Intubation on the first attempt was significantly greater in the DT group (90%) than in the ST group (35%). The intubation time was considerably shorter for the DT group (12.8 [7.8-16.9] s) when compared with the ST group (27.9 [16.3-91.0] s). Five patients were intubated by the alternative technique after failure to intubate for several attempts, and 3 cases were found to have a crease in the FVS after intubation in group ST. During topical anesthetic, three individuals in each group experienced transient oxygen desaturation. CONCLUSIONS: Our study discovered that the novel double setup tube could significantly improve the intubation success rate on the first attempt during AFOI for patients with challenging airway when a strategy based on a reduced gap between ETT and FB could not be applied.

Molecular oxygen enhances H2O2 utilization for the photocatalytic conversion of methane to liquid-phase oxygenates.

H2O2 is widely used as an oxidant for photocatalytic methane conversion to value-added chemicals over oxide-based photocatalysts under mild conditions, but suffers from low utilization efficiencies. Herein, we report that O2 is an efficient molecular additive to enhance the utilization efficiency of H2O2 by suppressing H2O2 adsorption on oxides and consequent photogenerated holes-mediated H2O2 dissociation into O2. In photocatalytic methane conversion over an anatase TiO2 nanocrystals predominantly enclosed by the {001} facets (denoted as TiO2{001})-C3N4 composite photocatalyst at room temperature and ambient pressure, O2 additive significantly enhances the utilization efficiency of H2O2 up to 93.3%, giving formic acid and liquid-phase oxygenates selectivities respectively of 69.8% and 97% and a formic acid yield of 486 µmolHCOOH·gcatalyst-1·h-1. Efficient charge separation within TiO2{001}-C3N4 heterojunctions, photogenerated holes-mediated activation of CH4 into ·CH3 radicals on TiO2{001} and photogenerated electrons-mediated activation of H2O2 into ·OOH radicals on C3N4, and preferential dissociative adsorption of methanol on TiO2{001} are responsible for the active and selective photocatalytic conversion of methane to formic acid over TiO2{001}-C3N4 composite photocatalyst.

AtNusG, a chloroplast nucleoid protein of bacterial origin linking chloroplast transcriptional and translational machineries, is required for proper chloroplast gene expression in Arabidopsis thaliana.

In Escherichia coli, transcription-translation coupling is mediated by NusG. Although chloroplasts are descendants of endosymbiotic prokaryotes, the mechanism underlying this coupling in chloroplasts remains unclear. Here, we report transcription-translation coupling through AtNusG in chloroplasts. AtNusG is localized in chloroplast nucleoids and is closely associated with the chloroplast PEP complex by interacting with its essential component PAP9. It also comigrates with chloroplast ribosomes and interacts with their two components PRPS5 (uS5c) and PRPS10 (uS10c). These data suggest that the transcription and translation machineries are coupled in chloroplasts. In the atnusg mutant, the accumulation of chloroplast-encoded photosynthetic gene transcripts, such as psbA, psbB, psbC and psbD, was not obviously changed, but that of their proteins was clearly decreased. Chloroplast polysomic analysis indicated that the decrease in these proteins was due to the reduced efficiency of their translation in this mutant, leading to reduced photosynthetic efficiency and enhanced sensitivity to cold stress. These data indicate that AtNusG-mediated coupling between transcription and translation in chloroplasts ensures the rapid establishment of photosynthetic capacity for plant growth and the response to environmental changes. Therefore, our study reveals a conserved mechanism of transcription-translation coupling between chloroplasts and E. coli, which perhaps represents a regulatory mechanism of chloroplast gene expression. This study provides insights into the underlying mechanisms of chloroplast gene expression in higher plants.

AtRsmD Is Required for Chloroplast Development and Chloroplast Function in Arabidopsis thaliana.

AtRsmD was recently demonstrated to be a chloroplast 16S rRNA methyltransferase (MTase) for the m2G915 modification in Arabidopsis. Here, its function of AtRsmD for chloroplast development and photosynthesis was further analyzed. The AtRsmD gene is highly expressed in green photosynthetic tissues. AtRsmD is associated with the thylakoid in chloroplasts. The atrsmd-2 mutant exhibited impaired photosynthetic efficiency in emerging leaves under normal growth conditions. A few thylakoid lamellas could be observed in the chloroplast from the atrsmd-2 mutant, and these thylakoids were loosely organized. Knockout of the AtRsmD gene had minor effects on chloroplast ribosome biogenesis and RNA loading on chloroplast ribosomes, but it reduced the amounts of chloroplast-encoded photosynthesis-related proteins in the emerging leaves, for example, D1, D2, CP43, and CP47, which reduced the accumulation of the photosynthetic complex. Nevertheless, knockout of the AtRsmD gene did not cause a general reduction in chloroplast-encoded proteins in Arabidopsis grown under normal growth conditions. Additionally, the atrsmd-2 mutant exhibited more sensitivity to lincomycin, which specifically inhibits the elongation of nascent polypeptide chains. Cold stress exacerbated the effect on chloroplast ribosome biogenesis in the atrsmd-2 mutant. All these data suggest that the AtRsmD protein plays distinct regulatory roles in chloroplast translation, which is required for chloroplast development and chloroplast function.

Perspective insights into hydrogels and nanomaterials for ischemic stroke.

Ischemic stroke (IS) is a neurological disorder prevalent worldwide with a high disability and mortality rate. In the clinic setting, tissue plasminogen activator (tPA) and thrombectomy could restore blood flow of the occlusion region and improve the outcomes of IS patients; however, these therapies are restricted by a narrow time window. Although several preclinical trials have revealed the molecular and cellular mechanisms underlying infarct lesions, the translatability of most findings is unsatisfactory, which contributes to the emergence of new biomaterials, such as hydrogels and nanomaterials, for the treatment of IS. Biomaterials function as structural scaffolds or are combined with other compounds to release therapeutic drugs. Biomaterial-mediated drug delivery approaches could optimize the therapeutic effects based on their brain-targeting property, biocompatibility, and functionality. This review summarizes the advances in biomaterials in the last several years, aiming to discuss the therapeutic potential of new biomaterials from the bench to bedside. The promising prospects of new biomaterials indicate the possibility of an organic combination between materialogy and medicine, which is a novel field under exploration.

A Novel Chloroplast Protein RNA Processing 8 Is Required for the Expression of Chloroplast Genes and Chloroplast Development in Arabidopsis thaliana.

Chloroplast development involves the coordinated expression of both plastids- and nuclear-encoded genes in higher plants. However, the underlying mechanism still remains largely unknown. In this study, we isolated and characterized an Arabidopsis mutant with an albino lethality phenotype named RNA processing 8 (rp8). Genetic complementation analysis demonstrated that the gene AT4G37920 (RP8) was responsible for the mutated phenotype. The RP8 gene was strongly expressed in photosynthetic tissues at both transcription and translation protein levels. The RP8 protein is localized in the chloroplast and associated with the thylakoid. Disruption of the RP8 gene led to a defect in the accumulation of the rpoA mature transcript, which reduced the level of the RpoA protein, and affected the transcription of PEP-dependent genes. The abundance of the chloroplast rRNA, including 23S, 16S, 4.5S, and 5S rRNA, were reduced in the rp8 mutant, respectively, and the amounts of chloroplast ribosome proteins, such as, PRPS1(uS1c), PRPS5(uS5c), PRPL2 (uL2c), and PRPL4 (uL4c), were substantially decreased in the rp8 mutant, which indicated that knockout of RP8 seriously affected chloroplast translational machinery. Accordingly, the accumulation of photosynthetic proteins was seriously reduced. Taken together, these results indicate that the RP8 protein plays an important regulatory role in the rpoA transcript processing, which is required for the expression of chloroplast genes and chloroplast development in Arabidopsis.

Study of Electrochemical Catalytic Coal Gasification: Gasification Characteristics and Char Structure Evolution.

Electrochemical catalytic coal gasification experiments with Fuxin (FX) coal under a CO2 atmosphere were conducted to evaluate the effects of power and temperature on coal gasification and char structure evolution during electrochemical catalytic gasification (ECG). When the power was 400 W, with temperature increasing from 800 to 1000 °C, the CO content in the gas products increased by 8.16%, the H2 content increased by 8.39%, and the CH4 concentration in the gas products initially increased and then decreased. When the temperature is 900 °C, with power increasing from 0 to 400 W, the CO content in the gas products increased by 58.27%, the H2 content increased by 81.33%, and the CH4 concentration in the gas products increased from 1.31 to 2.37%. The gasification reactivity and the concentration of combustible gas generated during ECG were higher than those during common coal gasification. Thermal electrons play important roles in ECG. These electrons could promote ring opening reactions and aromatic compound cracking and inhibit aromatization reactions while increasing the number of oxygen-containing functional groups in char, consequently enhancing the char gasification reactivity.

Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities.

Perforation behavior of 3 mm/3 mm double-spaced aluminum plates by PTFE/Al/W (Polytetrafluoroethylene/Aluminum/Tungsten) reactive projectiles with densities ranging from 2.27 to 7.80 g/cm3 was studied experimentally and theoretically. Ballistic experiments show that the failure mode of the front plate transforms from petalling failure to plugging failure as projectile density increases. Theoretical prediction of the critical velocities for the reactive projectiles perforating the double-spaced plates is proposed, which is consistent with the experimental results and well represents the perforation performance of the projectiles. Dimensionless formulae for estimating the perforation diameter and deflection height of the front plates are obtained through dimensional analysis, indicating material density and strength are dominant factors to determine the perforation size. High-speed video sequences of the perforation process demonstrate that high-density reactive projectiles make greater damage to the rear plates because of the generation of projectile debris streams. Specifically, the maximum spray angle of the debris streams and the crater number in the debris concentration area of the rear plate both increase with the projectile density and initial velocity.

Study of pyrolysis product distribution characteristics of lignite in the context of electrochemical catalytic gasification.

To support the effective utilization of lignite, which is abundant throughout China, and the problems associated with the existing common catalytic methods, electrochemical catalytic coal gasification (ECG) is proposed. As an important process in ECG, electrochemical catalytic pyrolysis (ECP) was studied. ECP experiments were performed on Fuxin coal. The influence of temperature and power (thermal electrons) on the generation of various pyrolysis products was studied. Char and tar production decreased as the temperature and power were increased. However, gaseous production increased with an increase in temperature and power. The thermal evolution and graphitization degree of coal char were increased as the temperature and power were increased. However, the degree of crystallite structure ordering of char and thermal evolution of coal char were still lower in ECP than in common coal pyrolysis (CCP). Unlike temperature, an increase in power increased the fractions of aliphatic and monocyclic aromatic compounds but decreased the fraction of fused-ring compounds. The proportions of CO and H2 in the gaseous products increased with temperature; those of other components decreased. However, the proportion of CO2 decreased with an increase in power, whereas the other components increased. Compared with CCP, ECP was more conducive to the full pyrolysis of coal and the formation of gaseous products. More aliphatic compounds and monocyclic compounds were present in tar produced by ECP than CCP; these were all beneficial to the subsequent gasification reaction. A deeper understanding of the action of thermal electrons on the whole ECG process would be useful.

Bulk Density Homogenization and Impact Initiation Characteristics of Porous PTFE/Al/W Reactive Materials.

In this research, the bulk density homogenization and impact initiation characteristics of porous PTFE/Al/W reactive materials were investigated. Cold isostatic pressed (CIPed) and hot temperature sintered (HTSed) PTFE/Al/W reactive materials of five different theoretical maximum densities were fabricated via the mixing/pressing/sintering process. Mesoscale structure characteristics of the materials fabricated under different molding pressures were compared while the effect of molding pressures on material bulk densities was analyzed as well. By using the drop weight testing system, effects of the theoretical maximum densities (TMDs), drop heights and molding pressures on the impact initiation characteristics were studied. Quantitatively, characteristic drop heights (H50) for different types of materials were obtained. The two most significant findings of this research are the density homogenization zone and the sensitivity transition zone, which would provide meaningful guides for further design and fabrication of reactive materials.

[Effect of total knee arthroplasty under computer navigation on intraoperative blood loss and joint function recovery].

OBJECTIVE: To analyze the effect of computer navigation assisted total knee arthroplasty on intraoperative hemorrhage and postoperative joint function recovery in patients with knee osteoarthritis. METHODS: From February 2015 to December 2017, 65 patients with knee osteoarthritis treated by traditional total knee arthroplasty were retrospectively analyzed as the control group and 65 patients with knee osteoarthritis treated by total knee arthroplasty under computer navigation as the experimental group. Before operation, all patients showed red swelling pain of knee, pain of going up and down stairs, and pain and discomfort of waist when sitting up and standing up. All patients were treated with total knee arthroplasty. The control group was treated with traditional total knee arthroplasty, and the experimental group was treated with total knee arthroplasty under the computer navigation system. The operation related conditions of the two groups were recorded and compared including the operation time and hospitalization time; the changes of hemoglobin and hematocrit of the two groups were detected and compared before and 5 days after the operation; the blood loss of the two groups and the induced flow at each time point calculated and compared after the operation, and the perioperative allogeneic blood transfusion rate and average blood transfusion volume of the patients were recorded; The joint function scale (KSS) was used to evaluate the recovery of knee joint function before the operation, 6 and 18 months after the operation respectively and to record the incidence of postoperative infection, lower extremity venous thrombosis and other complications. RESULTS: All the patients were successfully operated and the prognosis of the wound was good. All the patients were followed up for an average of 18 months. The operation time of the experimental group was longer than that of the control group, and the hospitalization time was shorter than that of the control group (P <0.05) ; the KSS score of the two groups at each time point after operation was higher than that before operation, but the increasing range of the test group was higher than that of the control group (P<0.05) ; there was no significant difference between the two groups in the incidence of complications (P>0.05) . CONCLUSION: Under the guidance of computer navigation, total knee arthroplasty can prolong the operation time compared with single total knee arthroplasty, but it is more conducive to reduce perioperative blood loss, reduce the rate of postoperative allogeneic blood transfusion, ideal recovery of joint function, less complications, safety and reliability.

Direct reduction of copper slag-carbon composite pellets by coal and biochar.

As a renewable resource of reducer, biochar prepared by pine sawdust is proposed for direct reduction of copper slag in this paper. Combined with thermodynamic analysis, effects of reduction time, temperature and CaO addition ratio on solid copper slag reduction characteristics are discussed. The oxides of iron in copper slag are Fe3O4 and 2FeO·SiO2. The reduction processes were carried out step by step for Fe3O4 and 2FeO·SiO2, respectively: Fe3O4 → FeO → Fe and 2FeO·SiO2 → Fe. The porous structure of biochar exhibits higher reduction reactivity and reaction rate than that of coal. CaO reduced the Gibbs free energy of reduction reactions and facilitated the reduction of 2FeO·SiO2 with C and CO. When CaO was added, separation reaction of FeO and SiO2 took place and α-SiO2 and ß-SiO2 were produced. When the addition ratio of CaO is above 0.3, CaO·SiO2 and 2CaO·SiO2 are produced. The reduction process of copper slag was established as follows: (a) dehydration and fast pyrolysis; (b) reduction of iron oxides by C and CO; and (c) sweating metallic iron outflows from cracks in pellet. Besides, direct reduction reaction mechanism and transport process of Cu are established based on reduction experiments, XRD and SEM-EDS analysis.

Low temperature selective catalytic reduction of nitric oxide with urea over activated carbon supported metal oxide catalysts.

Selective catalytic reduction of nitrogen oxides (SCR) with loaded urea is a method for removing NO under oxygen-rich and low-temperature conditions, which can solve the inhibitory effect of oxygen on the catalyst and the slip of ammonia. In present study, a series of activated carbon (wo-AC, co-AC, cs-AC and nu-AC) supported metal (Mn, Fe, Co, Cu and Zn) oxide catalysts with loading urea were prepared by ultrasonic assisted impregnation. The catalysts were used for NO removal at 50-120°C and characterized by XRD, SEM, GFAAS, EDS, XPS, BET and FTIR techniques. The effects of activated carbon type, loaded active element, metal oxides loading, temperature fluctuation on catalytic activity and the catalytic stability were also studied in this paper. The results indicated that nutshell-based activated carbon was more suitable as a carrier than other activated carbons, and urea-10Mn/nu-AC catalyst yielded a higher NO conversion than other catalysts. Besides, for used activated carbons, the larger specific surface area, more micropores distribution and the larger number of hydroxyl group and cyano terminal group are beneficial to the catalytic process. Moreover, the downward trend of NO conversion with increasing temperature suggested the adsorption of reactant gases played a crucial role in the catalytic process of urea-SCR.

mTERF8, a Member of the Mitochondrial Transcription Termination Factor Family, Is Involved in the Transcription Termination of Chloroplast Gene psbJ.

Members of the mitochondrial transcription terminator factor (mTERF) family, originally identified in vertebrate mitochondria, are involved in the termination of organellular transcription. In plants, mTERF proteins are mainly localized in chloroplasts and mitochondria. In Arabidopsis (Arabidopsis thaliana), mTERF8/pTAC15 was identified in the plastid-encoded RNA polymerase (PEP) complex, the major RNA polymerase of chloroplasts. In this work, we demonstrate that mTERF8 is associated with the PEP complex. An mTERF8 knockout line displayed a wild-type-like phenotype under standard growth conditions, but showed impaired efficiency of photosystem II electron flow. Transcription of most chloroplast genes was not substantially affected in the mterf8 mutant; however, the level of the psbJ transcript from the psbEFLJ polycistron was increased. RNA blot analysis showed that a larger transcript accumulates in mterf8 than in the wild type. Thus, abnormal transcription and/or RNA processing occur for the psbEFLJ polycistron. Circular reverse transcription PCR and sequence analysis showed that the psbJ transcript terminates 95 nucleotides downstream of the translation stop codon in the wild type, whereas its termination is aberrant in mterf8 Both electrophoresis mobility shift assays and chloroplast chromatin immunoprecipitation analysis showed that mTERF8 specifically binds to the 3' terminal region of psbJ Transcription analysis using the in vitro T7 RNA polymerase system showed that mTERF8 terminates psbJ transcription. Together, these results suggest that mTERF8 is specifically involved in the transcription termination of the chloroplast gene psbJ.

Impact-Induced Reaction Characteristic and the Enhanced Sensitivity of PTFE/Al/Bi2O3 Composites.

In this paper, the reaction characteristic of a novel reactive material, which introduced bismuth trioxide (Bi2O3) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), is studied. The effect of Bi2O3 with different content and particle size on the reaction behaviors of PTFE/Al/Bi2O3 are investigated by drop-weight test and X-ray diffractometer (XRD), including impact sensitivity, energy release performance under a certain impact, and reaction mechanism. The experimental results show that the content of Bi2O3 increased from 0% to 35.616%, the characteristic drop height of impact sensitivity (H50) of PTFE/Al/Bi2O3 reactive materials decreased first and then increased, and the minimum H50 of all types of materials in the experiment is 0.74 times that of PTFE/Al, and the particle size of Bi2O3 affects the rate of H50 change with Bi2O3 content. Besides, with the increase of Bi2O3 content, both the reaction intensity and duration first increase and then decrease, and there is optimum content of Bi2O3 maximizing the reaction degree of the PTFE/Al/Bi2O3. Furthermore, a prediction model for the impact sensitivity of PTFE-based reactive material is developed. The main reaction products include AlF3, xBi2O3·Al2O3, and Bi.

Penetration Behavior of High-Density Reactive Material Liner Shaped Charge.

The traditional polytetrafluoroethylene (PTFE)/Al reactive material liner shaped charge generally produces insufficient penetration depth, although it enlarges the penetration hole diameter by chemical energy release inside the penetration crater. As such, a novel high-density reactive material liner based on the PTFE matrix was fabricated, and the corresponding penetration performance was investigated. Firstly, the PTFE/W/Cu/Pb high-density reactive material liner was fabricated via a cold pressing/sintering process. Then, jet formation and penetration behaviors at different standoffs were studied by pulse X-ray and static experiments, respectively. The X-ray results showed that the PTFE/W/Cu/Pb high-density reactive material liner forms an excellent reactive jet penetrator, and the static experimental results demonstrated that the penetration depth of this high-density reactive jet increased firstly and then decreased by increasing the standoff. When the standoff was 1.5 CD (charge diameter), the penetration depth of this reactive jet reached 2.82 CD, which was significantly higher than that of the traditional PTFE/Al reactive jet. Moreover, compared with the conventional metal copper jet penetrating steel plates, the entrance hole diameter caused by this high-density reactive jet improved 29.2% at the same standoff. Lastly, the chemical reaction characteristics of PTFE/W/Cu/Pb reactive materials were analyzed, and a semi-empirical penetration model of the high-density reactive jet was established based on the quasi-steady ideal incompressible fluid dynamics theory.