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Impact detecting and counting are fundamental functions of fuses used in hard target penetration weapons. However, detection failure caused by battery breakdown in high-g acceleration environments poses a vulnerability for such weapons. This paper introduces a novel supercapacitor that combines energy storage and high-g impact detection, called self-sensing supercapacitor. By deliberately inducing a transient soft short-circuit during shock in the supercapacitor, it is possible to detect external impact by its transient voltage drop. To realize this concept, firstly, by introducing the contact theory and force-induced percolation model, the electrode strength and roughness are found to have key impacts on the formation of soft circuits. Subsequently, to meet the needs for sensitivity and capacity, a high-density porous carbon (HDPC) that combines high mechanical strength and porosity, is selected as a suitable candidate based on the analysis results. Furthermore, a two-step curing method is proposed to prepare the high-roughness HDPC (HRHDPC) electrode and to assemble the self-sensing supercapacitor. Due to the rich specific surface of the electrodes and the high surface strength and roughness conducive to the formation of transient soft short circuits, the self-sensing supercapacitor not only possesses an excellent specific capacitance (171 F/g at 0.5 A/g) but also generates significant voltage response signals when subjected to high-g impacts ranging from 8000g to 31,000g. Finally, the self-sensing supercapacitor is applied to compose a successive high-g impact counting system and compared to traditional solutions (sensors and tantalum capacitors) in the military fuzes. The results show that the self-sensing supercapacitor-based system exhibits advantages in terms of size, power consumption, and counting accuracy. [ABSTRACT FROM AUTHOR]

Bioderived carbon materials have garnered considerable interest in the fields of microwave absorption and shielding due to their reproducibility and environmental friendliness. In this study, KOH was evenly distributed on biomass Tremella using the swelling induction method, leading to the preparation of a three-dimensional network-structured hierarchical porous carbon (HPC) through carbonization. The achieved microwave absorption intensity is robust at −47.34 dB with a thin thickness of 2.1 mm. Notably, the widest effective absorption bandwidth, reaching 7.0 GHz (11–18 GHz), is attained at a matching thickness of 2.2 mm. The exceptional broadband and reflection loss performance are attributed to the 3D porous networks, interface effects, carbon network defects, and dipole relaxation. HPC has outstanding absorption characteristics due to its excellent impedance matching and high attenuation constant. The uniform pore structures considerably optimize the impedance-matching performance of the material, while the abundance of interfaces and defects enhances the dielectric loss, thereby improving the attenuation constant. Furthermore, the impact of carbonization temperature and swelling rate on microwave absorption performance was systematically investigated. This research presents a strategy for preparing absorbing materials using biomass-derived HPC, showcasing considerable potential in the field of electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

Existing GAN-based generative methods are typically used for semantic image synthesis. We pose the question of whether GAN-based architectures can generate plausible depth maps and find that existing methods have difficulty in generating depth maps which reasonably represent 3D scene structure due to the lack of global geometric correlations. Thus, we propose DepthGAN, a novel method of generating a depth map using a semantic layout as input to aid construction, and manipulation of well-structured 3D scene point clouds. Specifically, we first build a feature generation model with a cascade of semantically-aware transformer blocks to obtain depth features with global structural information. For our semantically aware transformer block, we propose a mixed attention module and a semantically aware layer normalization module to better exploit semantic consistency for depth features generation. Moreover, we present a novel semantically weighted depth synthesis module, which generates adaptive depth intervals for the current scene. We generate the final depth map by using a weighted combination of semantically aware depth weights for different depth ranges. In this manner, we obtain a more accurate depth map. Extensive experiments on indoor and outdoor datasets demonstrate that DepthGAN achieves superior results both quantitatively and visually for the depth generation task. [ABSTRACT FROM AUTHOR]

Cigar tobacco residues are a special air-cured tobacco material with increasing production in domestic. In this present study, the effect of glycerol addition on the pyrolysis characteristic, kinetic behavior, and release of pyrolytic products was investigated by using thermogravimetry coupled with online FTIR and self-built infrared tubular furnace. The thermal weight loss process of cigar tobacco could be divided into four stages, and the glycerol exhibited significant impact on the pyrolysis process. The stage II corresponding the decomposition of volatile components and hemicellulose shifted to the lower temperature accompanied with an increase of DTGmax and weight loss at this stage. The Ti, Tf, and residues were decreased, while the CPI was increased as for the CT-G sample, indicating an increased reactivity and comprehensive pyrolysis performance. Gauss peak fitting was used to separate the pyrolysis process of different pseudocomponents in the tobacco biomass. Pyrolysis kinetic analysis based on Coats-Redfern method showed that the activation energy for the decomposition of each pseudocomponents decreased after the addition of glycerol. The online FTIR and MS analysis also reflected the interaction between glycerol and biomass through the release of pyrolytic gaseous products. GC–MS was further used to analyze the compositions of pyrolytic products in the trapped particulate matter under different heating rates. High heating rate was beneficial for the sufficient release of pyrolysis products and aroma compounds. The glycerol addition inhibited the generation of alkaloids, phenols, esters, ketones, acids, and heterocyclic compounds, indicating some effect may exist between cigar tobacco and glycerol. [ABSTRACT FROM AUTHOR]

Periphyton is a complex community composed of diverse prokaryotes and eukaryotes; understanding the characteristics of microbial communities within periphyton becomes crucial for biogeochemical cycles and energy dynamics of aquatic ecosystems. To further elucidate the community characteristics of periphyton across varied aquatic habitats, including unpolluted ecologically restored lakes, aquaculture ponds, and areas adjacent to domestic and industrial wastewater treatment plant outfalls, we explored the composition and diversity of prokaryotic and eukaryotic communities in periphyton by employing Illumina MiSeq sequencing. Our findings indicated that the prokaryotic communities were predominantly composed of Proteobacteria (40.92%), Bacteroidota (21.01%), and Cyanobacteria (10.12%), whereas the eukaryotic communities were primarily characterized by the dominance of Bacillariophyta (24.09%), Chlorophyta (20.83%), and Annelida (15.31%). Notably, Flavobacterium emerged as a widely distributed genus among the prokaryotic community. Unclassified_Tobrilidae exhibited higher abundance in unpolluted ecologically restored lakes. Chaetogaster and Nais were enriched in aquaculture ponds and domestic wastewater treatment plant outfall area, respectively, while Surirella and Gomphonema dominated industrial sewage treatment plant outfall area. The alpha diversity of eukaryotes was higher in unpolluted ecologically restored lakes. pH and nitrogen content ( NO 2 - - N , NO 3 - - N , and TN) significantly explained the variations for prokaryotic and eukaryotic community structures, respectively. Eukaryotic communities exhibited a more pronounced response to habitat variations compared to prokaryotic communities. Moreover, the association networks revealed an intensive positive correlation between dominant Bacillariophyta and Bacteroidota. This study provided useful data for identifying keystone species and understanding their ecological functions. [ABSTRACT FROM AUTHOR]

Microplastics leaching from aging biodegradable plastics pose potential environmental threats. This study used response surface methodology (RSM) to investigate the impact of temperature, light, and humidity on the aging characteristics of polylactic acid (PLA). Key evaluation metrics included the C/O ratio, functional groups, crystallinity, surface topography, and mechanical properties. Humidity was discovered to have the greatest effect on the ageing of PLA, followed by light and temperature. The interactions between temperature and light, as well as humidity and sunlight, significantly impact the aging of PLA. XPS analysis revealed PLA underwent aging due to the cleavage of the ester bond (O–C=O), resulting in the addition of C=O and C–O. The aging process of PLA was characterized by alterations in surface morphology and augmentation in crystallinity, resulting in a decline in both tensile strength and elongation. These findings might offer insights into the aging behavior of degradable plastics under diverse environmental conditions. [ABSTRACT FROM AUTHOR]

During the thermal simulation compression test, the formation of an obvious bulge in the specimen leads to a certain deviation between the calculated and actual values of the true stress. The finite element method was used to simulate the single-pass compression of specimens of 34CrNi3MoV steel and obtain the actual nonuniform deformation of the bulging belly during the compression process, and the results were applied to correct experimental flow curves. The results showed that the deformation conditions had a significant influence on the nonuniformity of the specimen deformation during the compression process, and all the modified flow curves were lower than the original ones. The size of the bulge and the metal flow line in the finite element simulation were consistent with the test results. The load value obtained by using the modified flow curve was similar to the load value measured in the test, which indicated that the modified flow curve was very close to the real flow force curve of the material. The method used to modify the flow force curve is simple and practical. [ABSTRACT FROM AUTHOR]

Axon regeneration of dorsal root ganglia (DRG) neurons after peripheral axotomy involves reconfiguration of gene regulatory circuits to establish regenerative gene programs. However, the underlying mechanisms remain unclear. Here, through an unbiased survey, we show that the binding motif of Bmal1, a central transcription factor of the circadian clock, is enriched in differentially hydroxymethylated regions (DhMRs) of mouse DRG after peripheral lesion. By applying conditional deletion of Bmal1 in neurons, in vitro and in vivo neurite outgrowth assays, as well as transcriptomic profiling, we demonstrate that Bmal1 inhibits axon regeneration, in part through a functional link with the epigenetic factor Tet3. Mechanistically, we reveal that Bmal1 acts as a gatekeeper of neuroepigenetic responses to axonal injury by limiting Tet3 expression and restricting 5hmC modifications. Bmal1-regulated genes not only concern axon growth, but also stress responses and energy homeostasis. Furthermore, we uncover an epigenetic rhythm of diurnal oscillation of Tet3 and 5hmC levels in DRG neurons, corresponding to time-of-day effect on axon growth potential. Collectively, our studies demonstrate that targeting Bmal1 enhances axon regeneration. Injured peripheral neurons activate pro-growth gene programs, yet the mechanisms remain unclear. Here, the authors show that disruption of circadian clock factor Bmal1 accelerates axon regeneration through augmented epigenetic responses after injury. [ABSTRACT FROM AUTHOR]

Purpose: To assess the efficiency of [68 Ga]Ga-DOTA-FAPI-04 in diagnosing periprosthetic hip joint infection and establish a diagnostic standard of clinical significance based on uptake pattern. Methods: [68 Ga]Ga-DOTA-FAPI-04 PET/CT was performed in patients with symptomatic hip arthroplasty from December 2019 to July 2022. The reference standard was based on the 2018 Evidence-Based and Validation Criteria. Two diagnostic criteria, SUVmax and uptake pattern, were used to diagnose PJI. Meanwhile, original data were imported into IKT-snap to draw the view of interest, A.K. was used to extract features of clinical cases, and unsupervised clustering analysis was applied according to the groups. Results: A total of 103 patients were included, 28 of whom had PJI. The area under the curve of SUVmax was 0.898, which was better than that of all of the serological tests. The cutoff value of SUVmax was 7.53, and the sensitivity and specificity were 100 and 72%, respectively. The sensitivity, specificity and accuracy of the uptake pattern were 100, 93.1 and 95%, respectively. In radiomics analysis, the features of PJI were significantly different from those of aseptic failure. Conclusion: The efficiency of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in diagnosing PJI showed promising results, and the diagnostic criteria of the uptake pattern were more clinically instructive. Radiomics also showed certain application prospects in the field of PJI. Trial registration number: Trial registration: ChiCTR2000041204. Registered 24 September 2019. [ABSTRACT FROM AUTHOR]

Cobalt ferrite (CoFe2O4), with good chemical stability and magnetic loss, can be used to prepare composites with a unique structure and high absorption. In this study, CoFe2O4@mesoporous carbon hollow spheres (MCHS) with a core-shell structure were prepared by introducing CoFe2O4 magnetic particles into hollow mesoporous carbon through a simple in situ method. Then, the microwave absorption performance of the CoFe2O4@MCHS composites was investigated. Magnetic and dielectric losses can be effectively coordinated by constructing the porous structure and adjusting the ratio of MCHS and CoFe2O4. Results show that the impedance matching and absorption properties of the CoFe2O4@MCHS composites can be altered by tweaking the mass ratio of MCHS and CoFe2O4. The minimum reflection loss of the CoFe2O4@MCHS composites reaches -29.7 dB at 5.8 GHz. In addition, the effective absorption bandwidth is 3.7 GHz, with the thickness being 2.5 mm. The boosted microwave absorption can be ascribed to the porous core-shell structure and introduction of magnetic particles. The coordination between the microporous morphology and the core-shell structure is conducive to improving the attenuation coefficient and achieving good impedance matching. The porous core-shell structure provides large solid-void and CoFe2O4−C interfaces to induce interfacial polarization and extend the electromagnetic waves' multiple scattering and reflection. Furthermore, natural resonance, exchange resonance, and eddy current loss work together for the magnetic loss. This method provides a practical solution to prepare core-shell structure microwave absorbents. [ABSTRACT FROM AUTHOR]

The synthesis of wide bandwidth, thin thickness, and high performance microwave absorbing materials has become a hot topic of current research. Metal-organic frameworks with heterojunctions and porous structures are considered as suitable candidates to meet these characteristics. Herein, heterogeneous CoFe@N-doped porous carbon polyhedron composites were successfully synthesized via Fe2+ to replace Co in zeolite imidazole frame-67. The dielectric properties of composites were enhanced by the replacement of Fe2+, and the synergistic effect of dielectric loss and magnetic loss was realized. The petal-like lamellar structure increases the travel of electromagnetic (EM) waves, and the formation of porous structures improves impedance matching. Specifically, a reflection loss of −67.30 dB was obtained at a thickness of 2.88 mm, and an ultrabroad wide effective absorption bandwidth of 8.40 GHz was obtained, covering most of the X-band (8–12 GHz) and the whole Ku-band (12–18 GHz). The radar cross section (RCS) reduction value can reach 29.4 dB·m2, which means that the radar detector has a smaller probability of detecting targets. This work describes the unique advantages of metal ion replacement metal-organic frameworks derived materials in structural design, impedance matching, and performance adjustment, and provides a new reference for the field of electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

The laser shock adhesive-clinching (LSAC) is an original material joining technique that combines the advantages of clinch-bonded hybrid joining and laser shock clinching, in which two metal foils are bonded by adhesive and clinched by laser shock simultaneously. In this paper, the LSAC joints are manufactured by 1060 Al foils, Henkel EP 5055 adhesive, and perforated 304 stainless steel sheets. Through experiments and FEM simulations, the LSAC process and the deformation of LSAC joints under shear loads are analyzed, and the effect of adhesive on LSAC joint manufacturing is investigated. The results show that bulging is the dominant deformation behavior during LASC, and the cured adhesive with thin thickness is beneficial to the subsequent clinching process. The shear strength of the LSAC joint is greatly enhanced compared to the pure clinched and pure bonded joints. The shear failure process of the LSAC joint is adhesive degumming first, then the interlock separating. [ABSTRACT FROM AUTHOR]

The purpose of this article was to use finite element analysis (FEA) to study the relationship of tibial tunnel (TT) with fracture pattern and implants. A computed tomography scan of full-length tibia and fibula was obtained. Models were built after three-dimensional reconstruction. The corresponding plates and screws were constructed and assembled together with fracture models. FEA was performed and contourplots were output. The Von Mises stresses of nodes and displacements of elements were extracted. Student's t test was used to compare the values of Von Mises stresses and displacements between corresponding models. Differences in Von Mises stresses and displacements of fragments and implants between models with and without TT were nearly all statistically significant. However, the displacements of fragments and implants for all models were < 2 mm. TT in fracture models had larger Von Mises stresses than TT in intact tibial model. However, displacements of TT in fracture models showed similar or even smaller results to those in intact tibial model. Although almost all the tested parameters were statistically significant, differences were small and values were all below the clinical threshold. This study could promote open reduction and internal fixation with one-stage reconstruction for treatment of tibial plateau fractures associated with anterior cruciate ligament (ACL) ruptures. [ABSTRACT FROM AUTHOR]

The authors showcase the potential of symbolic regression as an analytic method for use in materials research. First, the authors briefly describe the current state-of-the-art method, genetic programming-based symbolic regression (GPSR), and recent advances in symbolic regression techniques. Next, the authors discuss industrial applications of symbolic regression and its potential applications in materials science. The authors then present two GPSR use-cases: formulating a transformation kinetics law and showing the learning scheme discovers the well-known Johnson–Mehl–Avrami–Kolmogorov form, and learning the Landau free energy functional form for the displacive tilt transition in perovskite LaNiO3. Finally, the authors propose that symbolic regression techniques should be considered by materials scientists as an alternative to other machine learning-based regression models for learning from data. [ABSTRACT FROM AUTHOR]

The article presents a case study of 56-year-old woman presented with 1-year left hip swelling after total hip arthroplasty (THA). It informs that the patient was treated with methylprednisolone 13 years ago due to erythema nodosum. It also informs that the patient had a previous history of type 2 diabetes and vitiligo. The cyst-like tissue was thoroughly removed and tissue culture and pathological examination were carried out.

Thermostable nanocomposites based on interpenetrating polymer network kaolin/cyanate ester (BADCy), derived from kaolin, bisphenol A dicyanate, and doped by 1-5 wt% KH550-modified kaolin nanoparticles, were synthesized and characterized using a dielectric strength tester, scanning electron microscope (SEM), dynamic mechanical analysis, thermogravimetric analysis techniques. A suitable addition of kaolin can enhance the mechanical properties, dielectric properties as well as reduce the dielectric loss of kaolin/BADCy copolymer. SEM analysis shows distinct characteristics of ductile fracture of the blends. In addition, the kaolin/BADCy nanocomposites has a better thermal stability compared with BADCy resin with the increasing of kaolin content. The moisture absorption increases linearly with the square root of time, and it follows the Fick’s second law. All these changes in properties are closely correlated to the kaolin/BADCy nanocomposites, which could form an interaction interface structure in the system. [ABSTRACT FROM AUTHOR]

Dysprosium doped chlorapatite, Ca5(PO4)3Cl:Dy3+ white-emitting phosphors were synthesized by a solid-state reaction method. The effects of synthesis temperature, Dy3+ doping concentration, Eu3+ co-doping concentration and charge compensator Li+ co-doping on the crystal structures and luminescence properties of Ca5(PO4)3Cl:Dy3+ samples were investigated. Ca5(PO4)3Cl:Dy3+, Eu3+ and Ca5(PO4)3Cl:Dy3+, Li+ phosphors with standard Ca5(PO4)3Cl structure were prepared by heating above 900 °C, and the doped Dy3+, Eu3+/Li+ ions had no effect on the crystal structure. Under ultraviolet excitation at 366 nm, the emission spectra of Ca5(PO4)3Cl:Dy3+ phosphors exhibited two characteristic peaks of Dy3+ at 484 and 577 nm, which corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 electron transitions, respectively. Both blue and yellow emissions within a single-component host would constitute the white light. The white emission intensity of Ca5(PO4)3Cl:Dy3+ was enhanced markedly by Li+ co-doping as charge compensator. Moreover, Eu3+ co-doped Ca5(PO4)3Cl:Dy3+ phosphor showed an excellent warm white light with high chromaticity coordinates and low correlated color temperature though an additional red emission of Eu3+. The results indicate that these Ca5(PO4)3Cl:Dy3+, Eu3+/Li+ phosphors have potential applications in the field of white light-emitting diodes as single-component white-emitting phosphors. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs)/ultra-high molecular weight polyethylene (UHMWPE) composites with a segregated structure had been fabricated using ethanol-assisted dispersion and hot compression at 180 °C. A percolation threshold of 3.5 wt% was achieved because of the formation conductive network. The positive temperature coefficient (PTC) and the negative temperature coefficient (NTC) effects of GNPs/UHMWPE composites had been investigated. The PTC behavior enhanced with increasing GNPs content but this was not always the case. The maximum PTC effect was observed in GNPs/UHMWPE composites (GNPs, 3.8 wt%) with the relatively low room temperature resistivity and the relatively high peak resistivity. The structure for GNPs/UHMWPE composites was examined by the SEM. The fact revealed that the slight interaction between GNPs and UHMWPE matrix may be changed by thermal cycles, and this can explain why thermal cycles could increase PTC and NTC intensity. [ABSTRACT FROM AUTHOR]

In this paper, titanium dioxide (TiO)/phenolphthalein-type polyimide (PPPI) composite was synthesized in situ polymerization, the diamino phenolphthalein type compound and dimethylacetamide as the matrix, and TiO as the filler. The mechanical property and thermal conductivity properties were used to characterize the properties of the obtained composite. A diamine monomer containing more benzene rings of phenolphthalein and an ether bond in its main chain were prepared, synthesized by a nucleophilic substitution reaction and a hydrazine hydrate reduction reaction. Polyimide composite had the same structure as that of a diamine monomer. And it was synthesized by solution imidization and heat imidization. The results showed that TiO improved the dispersibility, alignment and interfacial strength of the TiO/PPPI composite. The mechanical property of polyimide composite was increased with the increasing TiO loading. And a suitable addition of TiO could enhance the mechanical properties of polyimide system. Compared to polyimide resin, the TiO/PPPI composite had a higher thermal conductivity with the increasing of TiO content. All of these changes in properties were closely correlated with the TiO/PPPI composite, which could form an interaction interface structure in the system. [ABSTRACT FROM AUTHOR]

In order to acquire a series of solution-processable polyimides, synthesis of triazine-based diamine monomers 6-phenyl-1,3,5-triazine-2,4-diamine(PTDA) and 6-(4-fluorophenyl)-2,4-diamino-1,3,5-triazine(FPDT) was reported. On the basis of the synthesized diamines and a commercial available diamine, 6-methyl-1,3,5-triazine-2,4-diamine(MTDA), a series of polyimides(PIs), containing benzene or fluorobenzene as pendent group and triazine ring in the skeleton were synthesized. The two-step route constituted of ring-opening polymerization to form poly(amic acid)s (PAAs) and further thermal imidization to obtain the aiming PIs. Fourier transform infrared (FT-IR) was used for chemical structural characterization of the resulting PIs. The crystalline morphology of the PIs powder were explored by X-ray diffraction(XRD) patterns, and the minimum 2θ peak of PI-a split into to two peaks, which can be explained by result of coefficient between the torsion and 1,4 VDW energy with the help of calculation of Chem 3D Pro. Compared with common polyimides, most of the resulting PIs has excellent solubility in polar aprotic solvents, such as NMP, DMSO, DMAc and DMF. Meanwhile, after modification of diamine by the benzene or fluorobenzene as pendent group, PI-b (synthesized from PTDA and PMDA) and PI-c (synthesized from FPDT and PMDA) exhibited more excellent thermal stability compared with PI-a (synthesized from MTDA and PMDA) without sacrificing apparent solubility. Cyclic voltammetry(CV) method was used to investigate the electrochemical behavior of the resulting PIs, showing that electrochemical gap of PI-b and PI-c were 1.360 and 1.217 eV, respectively. By means of the thermogravimetric analysis(TGA) and the differential scanning calorimeter(DSC), the relationship between annealing temperature and thermal behavior of the resulting PI was discussed, revealed that 300-340 °C annealing render the PI best thermal behavior. Based on the performances, the resulting polyimides reveal their broad application prospect in polymer semiconductors. [ABSTRACT FROM AUTHOR]

In this study, micro-nano AlN co-filled PTFE composites were prepared by powder processing technique to obtain high performance electronic packaging materials with high thermal conductivity and outstanding thermal stability. The synergistic effect of micro-size and nano-size AlN particles on the thermal, mechanical, dielectric properties of the composites is systematically investigated. The SEM images indicate that nano-size AlN particles are filled into the interspaces between micro-size AlN particles, resulting in a tightly stacked structure in the composites. Compared with the PTFE composites with single-size AlN, the composites filled by 0.3 V micro-nano AlN display higher thermal conductivity (0.84 W/mK), and the thermal stability and mechanical properties of the composites are also enhanced. Meanwhile, the composites exhibit excellent dielectric properties: the maximum dielectric constant is 4.4 and dielectric loss is 0.0035 at 100 Hz. [ABSTRACT FROM AUTHOR]

In this work, benzoxazine/bismaleimide/cyanate ester (BOZ/BMI/BADCy) was prepared by bisphenol A benzoxazine, bisphenol A dicyanate, 4, 4′-bismaleimidodiphenyl methane, and organo-modified 2D montmorillonite (OMMt) nanoparticles. OMMt was synthesized and characterized using FTIR. The effect of different weight fraction of OMMt (0-5 wt%) on the dielectric, thermal, mechanical properties of the composites was investigated. All composites exhibited excellent dielectric properties and thermal stability endowed by BOZ/BMI/BADCy matrix. OMMt improves their dispersibility, alignment and interfacial strength and hence electrical conductivity and real permittivity increase with increasing OMMt loading, and a suitable addition of OMMt can enhance the mechanical properties, dielectric strength as well as reduce the dielectric loss of BOZ/BMI/BADCy terpolymer. The dielectric constant and dielectric loss of the sample with 4 wt% of OMMt filler was 3.56 and 0.004, at 1 kHz. The dielectric constant of the composites showed only a very small variation with frequency in the range 100-1 MHz. All these changes in properties are closely correlated to the OMMt/BOZ/BMI/BADCy nanocomposites, which could form an interaction interface structure in the system. [ABSTRACT FROM AUTHOR]

Thermostable nanocomposites based on interpenetrating polymer network bismaleimide/cyanate ester (BMI/CE) copolymer, derived from bisphenol A dicyanate, 4,4′-bismaleimidodiphenyl methane, and doped by 1-5 wt% organo-modified 2D montmorillonite (OMMt) nanoparticles were synthesized and characterized using a dielectric strength tester, concept 40 impedance analyzer, scanning electron microscope (SEM), dynamic mechanical analysis, and thermogravimetric analysis techniques. OMMt improves the dispersibility, alignment and interfacial strength of these nanocomposites, the electrical conductivity increase with increasing OMMt loading, and a suitable addition of OMMt can enhance the mechanical properties and dielectric property of BMI/CE copolymer. SEM analysis shows distinct characteristics of a ductile fracture of the blends. In addition, the OMMt/BMI/CE nanocomposites have a better thermal stability and a higher thermal conductivity compared to those of BMI/CE resin with the increasing of OMMt content. All of these changes in properties are closely correlated with the OMMt/BMI/CE nanocomposites, which could form an interaction interface structure in the system. [ABSTRACT FROM AUTHOR]

In this work, PTFE composites filled with Aluminum Nitride (AlN) were prepared by powder processing technique. The microstructure of AlN particles and the composites were investigated by scanning electron microscopic method. The effect of different weight fraction of AlN (0-0.6) on the dielectric, thermal, mechanical properties of the composites was investigated. All composites exhibited excellent thermal stability endowed by PTFE matrix. The dielectric constant and dielectric loss of the sample with 50 wt% of AlN filler was 4.2 and 0.006, at 1 MHz. The dielectric constant of the composites showed only a very small variation with frequency in the range 100-1 MHz. Several theoretical models were used to compare with experimental data of the dielectric constant of the composites. EMT model showed the best correlation with the experimental results. [ABSTRACT FROM AUTHOR]

The synthesis and thermal research of a pyridine-containing polyimide were reported in this work. The corresponding diamine monomer, 2,6-bis(4-(4-aminophenoxy)phenyl)-4-phenyl pyridine (BApPP), was synthesized through combining the nucleophilic aromatic substitution with modified Chichibabin reaction and hydrazine monohydrate reduction. Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance spectroscopy (H-NMR), and elemental analysis were used for chemical structural characterization, the results identified the chemical structures of the monomer and polymer. The melting behavior of the diamine monomer was studied by differential scanning calorimetry (DSC). The thermal properties of the resulting polyimide were investigated from DSC and thermo gravimetric analysis together. The results indicated the resulting polyimide exhibited excellent thermal stability, with the glass transition temperature around 275.0 °C and the initial mass loss of sample beyond 487.5 °C. The thermal decomposition process was analysed by combining the Avrami-Erofeev dynamic model and Ozawa-Flynn-Wall method. The coefficients of the thermal decomposition kinetics equation were calculated, and the final equation was obtained by polynomial fitting method. [ABSTRACT FROM AUTHOR]

We report the design and synthesis of a novel pyridine-containing triamine monomer, 2,6-bis(4-aminophenyl)-4-(4-aminophenoxy)pyridine (BAAP), through combining the nucleophilic aromatic substitution with modified Chichibabin reaction and hydrazine hydrate reduction. Based on it, a novel three-step route was applied in order to obtain a series of new polyimides, containing phthalimide as pendent group and pyridine moieties in main chains. The three-step route consisted of terminating the triamine by incorporating phthalic amic acid as pendant, ring-opening polymerization to form poly(amic acid)s and further chemical imidization to acquire polyimides. Nuclear Magnetic Resonance Spectroscopy (1H-NMR) was used for chemical structural characterization, and the results indicated the various forms of BAAP and branched structure units in the obtained polyimides. The morphology structures of the polyimides were evaluated by X-ray diffraction patterns, and the d-spacing values were found in the range of 4.14-4.65 Ǻ. Most of the resulting polyimides were soluble in polar aprotic solvents, such as NMP, DMF, DMAc, DMSO, and so on. Meanwhile, the polyimides exhibited excellent thermal stability, with the decomposition temperature at 5 and 10 % weight loss temperatures in the ranges of 399.1-461.1 °C and 481.1-566.9 °C, respectively. The polyimides, based on 6FDA, possessed the best comprehensive thermally stable and soluble performance. [ABSTRACT FROM AUTHOR]

Optical waveguide is used to guide the transmission of light. This paper reviews multilayer optical waveguide and some devices based on it. The optical waveguide can be divided into single-layer and multilayer optical waveguides in general. Here, multilayer cylindrical waveguide and multilayer planar waveguides were mainly focused. The analyzing method and the structures of waveguides were also demonstrated in briefly. Both these multilayer optical waveguide used in different kinds of optical devices including optical modulator, laser, optical amplifier, optical switch and special fiber were further presented. At last, the principle and structure of these multilayer optical devices were compared. [ABSTRACT FROM AUTHOR]

In this paper, several photonic generating methods for optical triangular pulses were reviewed. Four frontier research methods for generating optical triangular pulses were introduced, these four methods are respectively based on the frequency-to-time conversion, using normally dispersive fiber, by single-stage dual-drive Mach-Zehnder modulator (MZM), and using dual-parallel MZM. These four methods can be classified into two categories in terms of the optical source employed, such as mode-lock laser (MLL) and continuous-wave (CW) respectively. Compared with the methods based on MLL, those based on CW have many advantages, such as simpler structure, lower price, higher stability, more flexible and wider tunability. Besides, the method using single-stage drive MZM can generate versatile waveform optical pulses, which has better performance than the first two methods in tunable capability of both repetition rate and center wavelength. With the same driving signal applied, the optical source using the dual-parallel MZM can generate signal with higher frequency than that of using the single-stage MZM. [ABSTRACT FROM AUTHOR]

Chromium picolinate (CrPic) has been indicated to activate glucose transporter 4 (GLUT4) trafficking to the plasma membrane (PM) to enhance glucose uptake in 3T3-L1 adipocytes. In skeletal and heart muscle cells, insulin directs the intracellular trafficking of the fatty acid translocase/CD36 to induce the uptake of cellular long-chain fatty acid (LCFA). The current study describes the effects of CrPic and insulin on the translocation of CD36 from intracellular storage pools to the PM in 3T3-L1 adipocytes in comparison with that of GLUT4. Immunofluorescence microscopy and immunoblotting revealed that both CD36 and GLUT4 were expressed and primarily located intracellularly in 3T3-L1 adipocytes. Upon insulin or CrPic stimulation, PM expression of CD36 increased in a similar manner as that for GLUT4; the CrPic-stimulated PM expression was less strong than that of insulin. The increase in PM localization for these two proteins by insulin paralleled LCFA ([1-C]palmitate) or [H]deoxyglucose uptake in 3T3-L1 adipocytes. The induction of the PM expression of GLUT4, but not CD36, or substrate uptake by insulin and CrPic appears to be additive in adipocytes. Furthermore, wortmannin completely inhibited the insulin-stimulated translocation of GLUT4 or CD36 and prevented the increased uptake of glucose or LCFA in these cells. Taken together, for the first time, these findings suggest that both insulin and CrPic induce CD36 translocation to the PM in 3T3-L1 adipocytes and that their translocation-inducing effects are not additive. The signaling pathway inducing the translocations is different, apparently resulting in a differential activity of CD36. [ABSTRACT FROM AUTHOR]

Gasification is one potential way to use sewage sludge as renewable energy and solve the environmental problems caused by the huge amount of sewage sludge. In this paper, a three-dimensional Computational Fluid Dynamics (CFD) model has been developed to simulate the sewage sludge gasification process in a fluidized bed. The model describes the complex physical and chemical phenomena in the gasifier including turbulent flow, heat and mass transfer, and chemical reactions. The model is based on the Eulerian-Lagrangian concept using the nonpremixed combustion modeling approach. In terms of the CFD software FLUENT, which represents a powerful tool for gasifier analysis, the simulations provide detailed information on the gas products and temperature distribution in the gasifier. The model sensitivity is analyzed by performing the model in a laboratory-scale fluidized bed in the literature, and the model validation is carried out by comparing with experimental data from the literature. Results show that reasonably good agreement was achieved. Effects of temperature and Equivalence Ratio (ER) on the quality of product syngas (H2 + CO) are also studied. [ABSTRACT FROM AUTHOR]

Thousands of columns with special shape are analyzed by nonlinear numerical methods. The ductility is calculated to investigate the limit of the axial force ratio and circumstantial requirement for stirrups of an reinforced concrete (RC) column with special shape, in the point of view of the characteristic value for providing stirrup. The limit of the axial force ratio of columns with special shape in relation to the characteristic value of the stirrup is obtained. Then, the effect of stirrup arrangement on the ductility of the RC column is discussed in case of buckling of the longitudinal reinforcement and constraint concrete columns. The complete requirement for stirrups of RC column with special shape is given. [ABSTRACT FROM AUTHOR]

Focuses on the employment of finite element method to stimulate incompressible viscous unsteady flow in two-dimensional channel with a sudden expansion. Presentation of the streamline patterns and the velocity vector plots; Expansion of ratios; Analysis of the formation of eddies and energy loss in sudden expansion.

Studies the mathematical model of electrohydraulic speed control system with parallel pipelines. Increase of the damping ration of position control system; Improvement of response capacity of the system; Dynamic relation between pressure and flow rate along the pipelines.