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As an important constraint on the threshold voltage (Vt) distribution, the random telegraph noise (RTN) has attracted much attention due to the widely used multi-bit-per-cell technology in 3D NAND flash. This work investigated the physical mechanisms of RTN in charge- trap-based 3D NAND flash. According to statistical 3D TCAD simulation analysis, the fringing field from the control gate and the random discrete nitride trapped charges, two competitive mechanisms, are proposed to be responsible for the non-monotonic RTN behavior. As the programmed cell Vt level increases, the increasing fringing field from the control gate reduces the current-path percolation effect and the RTN amplitude. However, once the random discrete nitride trapped charges start to dominate the percolation current path, the RTN amplitude increases significantly. Instructively, the clarification of RTN competitive mechanisms contributes to compacting Vt distributions specifically in multi-level 3D NAND flash. [ABSTRACT FROM AUTHOR]

In this paper, the optimal temperature in an HMX spray-drying process was determined by molecular dynamics simulations and verified using experiments. Using the optimal spray-drying temperature determined by simulations, spherical β-HMX with a uniform particle size distribution was obtained by spray-drying. Performance characterization and thermal analysis of β-HMX were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The impact sensitivity of β-HMX was also measured and analyzed. The molecular dynamics simulations and experimental results both indicated that the optimum spray-drying temperature of HMX was 57°C. At this temperature, an HMX particle diameter range of 1 µm – 5 µm was obtained, and the particles tended to be smooth spheroids. Compared with raw HMX, the Tp0 and critical temperature of thermal explosion of HMX-1 increased by 0.9°C and 0.94°C, respectively. The characteristic drop height of impact sensitivity increased by 32% from 32.05 cm to 42.28 cm. [ABSTRACT FROM AUTHOR]

We proposed with excitement a novel molecular co-assembly (MCSA) that can effectively overcome the agglomeration of energetic materials. Through the coordinated self-assembly of polymethyl methacrylate-polyvinyl acetate (PMMA-PVA) with honeycomb-like structure and nanoparticles, a controlled and orderly distribution of nitroamine explosive (cyclotetramethylenetetranitramine, HMX; cyclotrimethylenetrinitramine, RDX; and hexanitrohexaazaisowurtzitane, CL-20) structure was achieved, above all, resolving the agglomeration problem availably. The modification ability of PMMA to RDX, HMX, and CL-20 at different temperatures was simulated by Materials Studio, which provided guidance for the ambient temperature of collaborative self-assembly. In order to compare the priority of the morphology and performance, RDX/PMMA-PVA, HMX/PMMA-PVA, and CL-20/PMMA-PVA composite particles with the same PMMA content were also fabricated by water suspension coating method, respectively. Structural characterizations and thermal stability of the composites were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier-transform infrared (FT-IR) spectra, and differential scanning calorimeter (DSC). Moreover, the safety performance was analyzed by qualitative testing of impact sensitivity and friction sensitivity. The solid spherical PBX prepared via collaborative self-assembly all exhibited a perfect spherical structure, smooth, and flat coating, without any agglomeration. They had the same crystalline structure as the uncoated explosives, simultaneously demonstrating lower impact sensitivity and higher energy performance. The application of collaborative self-assembly technology has broken through the key technical bottleneck of the shell material being easy to form a separate phase in the desensitization coating of explosives, availably resolved the problems of particle exposure and low coverage during the coating, thus possessing vital significance for reference in the design and fabrication of PBXs with core-shell structure. [ABSTRACT FROM AUTHOR]

In this paper, a novel functional magnetic nano-demulsifier with efficient oil–water separation and recyclability was prepared by one-pot method. Magnetic fluorinated polyether composite demulsifier (Fe 3 O 4 @C-F) was prepared by combining Fe 3 O 4 as magnetic matrix with carbon nanospheres and grafting fluorinated polyether. The morphology and structure of the composites were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The results showed that carbon nanospheres and fluorinated polyether were successfully compounded on Fe 3 O 4 , and the crystallinity of the composites was improved. The demulsification experiment and recovery performance test were carried out with the self-made crude oil emulsion. The main factors affecting the demulsification performance of demulsifier and its demulsification mechanism were discussed. The results showed that the demulsification effect of Fe 3 O 4 @C-F was the best when the dosage was 600 ppm, 65 °C, 120 min and pH value was 6. The demulsification rate could reach 96.68%, and the oil–water interface was clear. Fe 3 O 4 @C-F had magnetic response, and could be recycled and reused 5 times from two-phase system under external magnetic field. The application of carbon materials in the field of oil–water separation has injected a new power source for the application of carbon nanomaterials in the field of demulsifiers. [ABSTRACT FROM AUTHOR]

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times. [ABSTRACT FROM AUTHOR]

Polyimide (PI) has been widely used to manufacture flexible films in aerospace, electronics and other fields because of its flexibility, thermal resistance, etc. However, the thermal conductivity of PI is relatively low, restricting the wider applications of PIs. This review discusses the research progress during recent five years in the preparation of filled-type PI composites with high thermal conductivity and flexibility. In addition, this review introduces four types of fillers, including boron nitride, graphene (or graphite oxide), carbon nanotubes and carbon nitride, as well as four popular preparation methods, the arrangement and surface modification of fillers, the microstructure design of composites and the synergistic effect of different fillers, and explicitly explains the different action mechanisms between them. These methods provide suggestions to balance the relationship amongst thermal conductivity, flexibility and mechanical properties of preparing filled-type PI composites. In addition, this article also introduces the current application status and future prospects of PI composite materials in advanced materials. [ABSTRACT FROM AUTHOR]

We have investigated the effective utilization potential of carbon nanomaterials in the field of pour point depressants, and reported three kind of carbon-based hybrid nano-pour-point depressants with different dimensions. In this paper, poly-α-olefins-acrylate high-carbon ester pour point depressant (PAA-18) was prepared by esterification and polymerization as the basic pour point depressant. Then, the basic pour point depressant PAA18 was modified by solvothermal method with graphene oxide (GO), carbon nanospheres (Cna) and carbon nanotubes (OCNTs). The morphology and structure of the composites were analyzed by SEM, FTIR and XRD. The results showed that PAA18 was successfully in situ polymerized on GO, Cna and OCNTs. We took the simulated oil as the experimental object, and evaluated its pour point, rheological properties and wax crystal morphology, and achieved excellent results. In the three carbon-based hybrid nano-pour-point depressants with different carbon contents, the oxidation carbon nanotubes composite pour point depressant (PAA18-1 % OCNTs) with carbon content of 1 % had the best pour point and viscosity reduction effect when the dosage was 1250 ppm, which could make the pour point of the simulated oil containing wax decrease by 16 °C. PAA18-1 % OCNTs reduced the pour point by 5 °C more than PAA18. This paper provides reference for the application of carbon nanomaterials in the field of pour point depressant. [ABSTRACT FROM AUTHOR]

Herein, a novel quinary high-entropy rare earth disilicate (Sm 0.2 Eu 0.2 Tb 0.2 Dy 0.2 Lu 0.2) 2 Si 2 O 7 ((5RE 1/5) 2 Si 2 O 7) porous ceramics were synthesized through a sol-gel/vacuum freeze-drying method with high-temperature calcination process. The microstructure, phase composition, thermal conductivity, compressive strength, and thermal stability of the as-prepared (5RE 1/5) 2 Si 2 O 7 porous ceramics were systematically investigated. The results indicated that the samples possess high porosity of 76.83%, pore size of 0.3–1.2 μm, homogeneous microstructure with small grain size of 400–800 nm, which results in low thermal conductivity of 0.94 W/(m·K) at 1273 K and high compressive strength of 6.55 MPa. These excellent properties indicated that as-prepared (5RE 1/5) 2 Si 2 O 7 porous ceramics has a great potential application value in the field of high-temperature thermal insulation materials. • The as-prepared porous (5RE 1/5) 2 Si 2 O 7 ceramics perform a high porosity of 76.83%. • The as-prepared porous (5RE 1/5) 2 Si 2 O 7 ceramics present low thermal conductivity of 0.94 W/(m·K) at 1273 K. • Has a great potential application value in the field of high-temperature thermal insulation materials. [ABSTRACT FROM AUTHOR]

Mitochondria is essential for cellular energy production, oxidative stress, and apoptosis. Mitochondrial DNA (mtDNA) encodes essential proteins for mitochondrial function. Although several studies have explored the association between changes in mtDNA copy number (mtDNA-CN) and risk of mental disorders, the results remain debated. This study used a bidirectional two-sample Mendelian randomization (MR) analysis to examine the genetic causality between mtDNA-CN and mental disorders. Genome-wide association study (GWAS) data for mtDNA-CN were sourced from UK biobank, involving 383,476 European cases. GWAS data for seven mental disorders—attention deficit/hyperactivity disorder, autism spectrum disorder (ASD), schizophrenia, bipolar disorder, major depressive disorder, anxiety, and obsessive-compulsive disorder—were primarily obtained from the Psychiatric Genomics Consortium. Causal associations were assessed using inverse variance weighting, with sensitivity analyses via the weighted median and MR-Egger methods. Reverse MR considered the seven mental disorders as exposures. All analyses were replicated with additional mtDNA-CN GWAS data from 465,809 individuals in the Heart and Ageing Research in Genomic Epidemiology consortium and the UK Biobank. Forward MR observed a 27 % decrease in the risk of ASD per standard deviation increase in genetically determined blood mtDNA-CN (OR = 0.73, 95%CI: 0.58–0.92, p = 0.002), with no causal effects on other disorders. Additionally, reverse MR did not indicate a causal association between any of the mental disorders and mtDNA-CN. Validation analyses corroborated these findings, indicating their robustness. Our study supports the potential causal association between mtDNA-CN and the risk of ASD, suggesting that mtDNA-CN could serve as a promising biomarker for early screening of ASD. • The association between mtDNA-CN and risk of mental disorder remain debated. • Lower genetically determined blood mtDNA-CN was associated with higher risk of ASD. • No causal effects of mtDNA-CN on ADHD, SCZ, BD, MDD, anxiety, and OCD were found. • Reverse MR indicated no causal link between any mental disorders and mtDNA-CN. [ABSTRACT FROM AUTHOR]

In order to solve the problem of demulsification of oil-water emulsion, a new type of highly efficient and recyclable magnetic fluorine-containing polyether composite demulsifier (Fe3O4@Ti-F) was synthesized. Fe3O4@Ti-F was prepared by one-pot method to combine magnetic nanomaterial TiO2 with Fe3O4 and graft fluorinated polyether. The successful synthesis of Fe3O4@Ti-F was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XPS). The demulsification performance of Fe3O4@Ti-F was evaluated by using the self-made crude oil emulsion as the experimental object. The demulsification mechanism of the demulsifier and the influence of external factors such as temperature and pH on the demulsification performance of the demulsifier were discussed, and the amount of TiO2 in the preparation process was determined. The results show that the demulsification efficiency of 50:50 (v/v %) W/O emulsion can reach 90.83% when the dosage of Fe3O4@Ti-F is 600 mg/L, the temperature is 65 °C and the time is 30 min. In the neutral acid environment, the demulsification rate of the demulsifier is above 80%. In addition, Fe3O4@Ti-F has been proved to have good magnetic effect. Under the action of external magnetic field, it can be recovered and recycled from the two-phase system for 4 times, and its demulsification efficiency is still above 60%. Fe3O4@Ti-F will have broad application prospects in the field of oil-water separation in an energy-saving way. [ABSTRACT FROM AUTHOR]

In order to improve the general problem of irregular coating morphology and low mechanical strength of the coating layer in existing coating desensitization technology, nano-cyclotrimethylene trinitramine/melamine-urea-formaldehyde (RDX/MUF) composite energetic microspheres were prepared by an improved emulsion polymerization, taking the MUF as the binder and RDX as the main explosive. In order to judge whether RDX/MUF possessed good stability, the combination of differential scanning calorimetry (DSC) and molecular dynamics (MD) simulation was used to determine the level of binding binding energy between urea-formaldehyde resin binder (UF) and RDX. In addition, to investigate the optimal reaction temperature for the preparation of MUF/RDX, the binding energy between UF and RDX at different temperatures was simulated. And then the morphology and thermal properties of the as-prepared composite energetic microspheres were analyzed by scanning electron microscopy (SEM) and DSC, the impact sensitivity and friction sensitivity of the resultant samples were tested as well. Moreover, RDX/MUF with the same MUF content was prepared by physical mixing for comparative analysis. MD simulation demonstrated that UF and RDX possessed good binding ability at 298 K. The DSC method indicatec that UF and RDX had good compatibility, and the comprehensive performance of RDX after coating was not significantly deteriorated; The optimal binding temperature between UF and RDX was 60~70 °C which is consistent with the experimental results. The experimental results showed that the optimum process conditions for the preparation of RDX/MUF could be listed as follows: the temperature for preparing RDX/MUF composite energetic microspheres by the improved emulsion polymerization was 70 °C the optimal pH value of the urea-formaldehyde resin prepolymer solution was 3, and the optimal melamine-urea molar ratio was 0.4. [ABSTRACT FROM AUTHOR]