Unusual polypyrrole/graphene/cellulose nanofibril (PPy/GR/CNF) composite particles were fabricated by introducing an in situ oxidative polymerization approach. Structural characterization of the ...composite particles showed foam-like network morphology with a large surface area of 621 m2/g. The PPy/GR/CNF sample exhibited remarkable capacitance behavior in 1 M Na2SO4. It showed a high specific capacitance of 264.3 F/g at 0.25 A/g, which represents a 51.7% increase compared to that of PPy/GR and a high capacitance of 155.5 F/g even at a high current density of 5 A/g. Meanwhile, it possessed high rate capability and good cycling performance (85.7% capacitance retention even after 1000 cycles). These excellent electrochemical performances were attributed to the structure of PPy/GR/CNF that can provide large surface areas and shorten electron diffusion pathways. More importantly, the CNF stabilized the structure of PPy and prevented chain breakdown during the charge/discharge process, which improved the cycling performance. Hence, this PPy/GR/CNF composite shows great potential for the fabrication of high-capacitance and low-cost supercapacitor electrode materials with good cycling performance.
The temperature and strain fields monitoring during the preparation process of buoyancy materials, as well as the health status after molding, are important for mastering the mechanical properties of ...buoyancy materials and ensuring the safety of operators and equipment. This paper proposes a short and high-density femtosecond fiber Bragg grating (fs-FBG) array based on different temperature coefficients fibers. By optimizing the parameters of femtosecond laser point-by-point writing technology, high-performance fs-FBG arrays with millimeter level gating length and millimeter level spatial resolution were prepared on two types of fibers. These were successfully embedded in buoyancy materials to achieve in-situ online monitoring of the curing process and after molding. The experimental results show that the fs-FBG array sensor has good anti-chirp performance and achieves online monitoring of millimeter-level spatial resolution. Intelligent buoyancy materials can provide real-time feedback on the health status of equipment in harsh underwater environments. The system can achieve temperature monitoring with an accuracy of 0.56 °C and deformation monitoring with sub-millimeter accuracy; the error is in the order of micrometers, which is of great significance in the field of deep-sea exploration.
In this paper, we propose a new lightweight block cipher named RECTANGLE. The main idea of the design of RECTANGLE is to allow lightweight and fast implementations using bit-slice techniques. ...RECTANGLE uses an SP-network. The substitution layer consists of 16 4×4 S-boxes in parallel. The permutation layer is composed of 3 rotations. As shown in this paper, RECTANGLE offers great performance in both hardware and software environment, which provides enough flexibility for different application scenario. The following are 3 main advantages of RECTANGLE. First, RECTANGLE is extremely hardware-friendly. For the 80-bit key version, a one-cycle-per-round parallel implementation only needs 1600 gates for a throughput of 246 Kbits/s at 100 kHz clock and an energy efficiency of 3.0 pJ/bit. Second, RECTANGLE achieves a very competitive software speed among the existing lightweight block ciphers due to its bit-slice style. Using 128-bit SSE instructions, a bit-slice implementation of RECTANGLE reaches an average encryption speed of about 3.9 cycles/byte for messages around 3000 bytes. Last but not least, we propose new design criteria for the RECTANGLE S-box. Due to our careful selection of the S-box and the asymmetric design of the permutation layer, RECTANGLE achieves a very good security-performance tradeoff. Our extensive and deep security analysis shows that the highest number of rounds that we can attack, is 18 (out of 25).
Intervertebral disc degeneration (IDD) is a common disease that increases with age, and its occurrence is stressful both psychologically and financially. Stem cell therapy for IDD is emerging. For ...this therapy, stem cells from different sources have been proven in vitro, in vivo, and in clinical trials to relieve pain and symptoms, reverse the degeneration cascade, delay the aging process, maintain the spine shape, and retain mechanical function. However, further research is needed to explain how stem cells play these roles and what effects they produce in IDD treatment. This review aims to summarize and objectively analyse the current evidence on stem cell therapy for IDD.
The characteristic absorption spectra of three positional isomers of hydroxybenzoic acid are measured using a terahertz time-domain spectroscopy system (THz-TDS) in the 0.6-2.0 THz region at room ...temperature. Significant differences in their terahertz spectra are discovered, which indicates that THz-TDS is an effective means to identify positional isomers. In order to simulate their spectra, the seven molecular clusters of 2-, 3-, and 4-hydroxybenzoic acid (2-, 3-, and 4-HA) are calculated using the DFT-D3 method. Additionally, the potential energy distribution (PED) method is used to analyze their vibration modes. The analysis indicates that the vibration modes of 2-HA are mainly out-of-plane angle bending and bond angle bend in plane. The vibration modes of 3-HA are mainly bond length stretch and dihedral angle torsion. The vibration modes of 4-HA are mainly bond angle bend in plane and dihedral angle torsion. Interaction region indicator (IRI) analysis is used to visualize the location and type of intermolecular interactions in 2-, 3-, and 4-HA crystals. The results show that the weak interaction type of 2-, 3-, and 4-HA is dominated by van der Waals (vdW) interaction. Therefore, we can confirm that terahertz spectroscopy detection technology can be used as an effective means to identify structural isomers and detect the intermolecular interactions in these crystals. In addition, it can explain the absorption mechanism of terahertz waves interacting with matter.
Gangba sheep as a famous breed of Tibetan sheep, its wool color is mainly white and black. Gangba wool is economically important as a high-quality raw material for Tibetan blankets and Tibetan serge. ...However, relatively few studies have been conducted on the wool color of Tibetan sheep. To fill this research gap, this study conducted an in-depth analysis of two populations of Gangba sheep (black and white wool color) using whole genome resequencing to identify genetic variation associated with wool color. Utilizing PCA, Genetic Admixture, and N-J Tree analyses, the present study revealed a consistent genetic relationship and structure between black and white wool colored Gangba sheep populations, which is consistent with their breed history. Analysis of selection signatures using multiple methods (F.sub.ST, Ï ratio, Tajima's D), 370 candidate genes were screened in the black wool group (GBB vs GBW); among them, MC1R, MLPH, SPIRE2, RAB17, SMARCA4, IRF4, CAV1, USP7, TP53, MYO6, MITF, MC2R, TET2, NF1, JAK1, GABRR1 genes are mainly associated with melanin synthesis, melanin delivery, and distribution. The enrichment results of the candidate genes identified 35 GO entries and 19 KEGG pathways associated with the formation of the black phenotype. 311 candidate genes were screened in the white wool group (GBW vs GBB); among them, REST, POU2F1, ADCY10, CCNB1, EP300, BRD4, GLI3, and SDHA genes were mainly associated with interfering with the differentiation of neural crest cells into melanocytes, affecting the proliferation of melanocytes, and inhibiting melanin synthesis. 31 GO entries and 22 KEGG pathways were associated with the formation of the white phenotype. This study provides important information for understanding the genetic mechanism of wool color in Gangba, and provides genetic knowledge for improving and optimizing the wool color of Tibetan sheep. Genetic improvement and selective breeding to produce wool of specific colors can meet the demand for a diversity of wool products in the Tibetan wool textile market.
The source rock quality, organic pore structure, occurrence state and sealing mechanisms of shale gas in the Ordovician Wufeng – SilurianLongmaxi Formation (O3w-S1l), Fuling region, Sichuan Basin ...were studied using a series of techniques including ultra-microscopic organic maceral identification, FIB-SEM, high temperature/pressure isothermal adsorption and isotopic age dating of noble gas. The results show that: (1) O3w-S1l organic-rich shale was mainly formed in a sedimentary environment with high productivity in surface water and hypoxia in bottom water, which can be divided into two sections according to TOC. The lower section (TOC≥3%) is mainly composed of graptolite, phytoplankton, acritarch, bacteria and solid bitumen. Graptolite is the main contributor to TOC, but the shale gas is mainly derived from hydrogen-rich organic matter such as phytoplankton, acritarch and pyrolysis of liquid hydrocarbons produced by hydrogen-rich organic matter. (2) Organic pores, as principal reservoir space for shale gas, exist in hydrogen-rich organic matter and solid bitumen. The graptolites and plenty of other organic matter stacking distribution in lamina provide both reservoir space for supplement and effective pathways of connected pores for shale gas. (3) Shale gas in Fuling region is in supercritical state and dominated by free gas. The match of formation time of closed shale gas system and gas-generation peak, as well as slight alteration degree of sealing conditions in the later stage, are key factors controlling the retention and accumulation of shale gas in the regions with high thermal maturity and complex tectonic background. Adsorption, capillary sealing and slow diffusion of shale are the main microscopic mechanisms for the retention and accumulation of shale gas. It thus can be seen that the generation and accumulation of marine shale gas with high thermal maturity in complex structure areas is controlled jointly by anoxic depositional environment, excellent hydrocarbon rock quality, superior reservoir space and favorable sealing conditions.
We demonstrate an electrically triggered tunable terahertz (THz) band-pass filter based on vanadium dioxide (VO 2 ) embedded hybrid metamaterials. The unit cell of the filter consists of two cross ...resonators and a central bar. The phase transition of VO 2 is induced by the ohmic heating of the central bar. The transmission can be modulated by the applied currents. The mechanism of tunability is that the conductivity of the VO 2 film changes with the applied currents. The relation between the upper cut-off frequency and the geometries is investigated using finite integration time domain method. The sample is fabricated by a thin film process, and characterized using a THz time domain spectroscopy system. The results show that, when the bias current rises from 0 to 0.27 A, the transmission decreases from 0.85 to 0.01. The maximum modulation depth reaches 96%, and the full width at half maximum is about 0.44 THz. This tunable THz band-pass filter has potential applications in THz communication, imaging, and spectroscopy systems.
In this study, the terahertz (THz) spectra of C
S were obtained in the 0.4-2.3 THz frequency range using different sample preparation methods. In the spectra, a sharp absorption peak of C
S was found ...at 2.03 THz. Under controlled conditions, the mass ratio of C
S was the most critical factor affecting the strength of the absorption peak, and the absorption coefficient followed the Beer-Lambert law, exhibiting a linear relationship with the mass ratio of C
S. The intrinsic dielectric constants of C
S and polyethylene (PE) were calculated in accordance with the Maxwell-Garnett (MG), Bruggeman (BM), and Landau-Lifshitz-Loovenga (LLL) models, using two-phase composite samples. The results show that the LLL model had the highest accuracy.
It is important for equipment to operate safely and reliably so that the working state of mechanical parts pushes forward an immense influence. Therefore, in order to enhance the dependability and ...security of mechanical equipment, to accurately predict the changing trend of mechanical components in advance plays a significant role. This paper introduces a novel condition prediction method, named error fusion of hybrid neural networks (EFHNN), by combining the error fusion of multiple sparse auto-encoders with convolutional neural networks for predicting the mechanical condition. First, to improve prediction accuracy, we can use the error fusion of multiple sparse auto-encoders to collect multi-feature information, and obtain a trend curve representing machine condition as well as a threshold line that can indicate the beginning of mechanical failure by computing the square prediction error (SPE). Then, convolutional neural networks predict the state of the machine according to the original data when the SPE value exceeds the threshold line. It can be seen from this result that the EFHNN method in the prediction of mechanical fault time series is available and superior.
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