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Accurate angular position detection is indispensable for high-precision angular speed output of the gimbal servo system in single gimbal control moment gyro (SGCMG). However, the nonideal characteristics of resolver output signals introduce systematic errors in angular position detection, consequently impacting the accuracy of gimbal angular speed output. The compact structure of SGCMG prohibits the attachment of high-precision sensors for resolver calibration due to space constraints. Therefore, a self-calibration method based on signal reconstruction is proposed to suppress the resolver systematic error. The angular speed control error is fed into the co-frequency notch filter for iterating. Subsequently, the sine and cosine coefficients of the systematic error are identified, and the coefficient tables are established. The systematic error is then reconstructed according to the coefficient tables and compensated in the angular position feedback link. Simulation analysis is employed to assess the stability and dynamic performance of the closed-loop system. Experimental verification confirms that the proposed method can effectively suppress the systematic error of the resolver and improve the angular position detection accuracy, which further improve the precision of the gimbal angular speed.

A Ti3C2Tx/MoS2/MWCNT@rGONR nanocomposite was prepared for the first time for building a sensitive electrochemical aptasening platform to simultaneously detect kanamycin (Kana) and chloramphenicol (Cap). Owing to their accordion-like structure, rich surface groups, and high charge mobility, Ti3C2Tx/MoS2/MWCNT@rGONR composites provided a spacious covalent immobilization surface and a better electrochemical aptasensing platform. The aptamers of Kana and Cap used in sensors enhance the selectivity. Furthermore, TiP, an ion exchanger, was used for loading more different metal ions functioning as labels to form a sandwich-type sensor together with Ti3C2Tx/MoS2/MWCNT@rGONR, improving the electrochemical sensitivity and obtaining a highly distinguishable signal readout. Under the optimized conditions, the sensor has good detection limits of 0.135 nmol L−1and 0.173 nmol L−1for Kana and Cap, respectively, at the same linearity concentration of 0.5–2500 nmol L−1. Finally, it was successfully applied for detection in milk and fish meat, and the results were compared with the standard method HPLC, indicating its great potential for food safety monitoring.

Spatially-coupled (SC) codes, known for their threshold saturation phenomenon and low-latency windowed decoding algorithms, are ideal for streaming applications and data storage systems. SC codes are constructed by partitioning an underlying block code, followed by rearranging and concatenating the partitioned components in a convolutional manner. The number of partitioned components determines the memory of SC codes. In this paper, we investigate the relation between the performance of SC codes and the density distribution of partitioning matrices. While adopting higher memories results in improved SC code performance, obtaining finite-length, high-performance SC codes with high memory is known to be computationally challenging. We break this computational bottleneck by developing a novel probabilistic framework that obtains (locally) optimal density distributions via gradient descent. Starting from random partitioning matrices abiding by the obtained distribution, we perform low-complexity optimization algorithms that minimize the number of detrimental objects to construct high-memory, high-performance quasi-cyclic SC codes. We apply our framework to various objects of interest, from the simplest short cycles, to more sophisticated objects such as concatenated cycles aiming at finer-grained optimization. Simulation results show that codes obtained through our proposed method notably outperform state-of-the-art SC codes with the same constraint length and optimized SC codes with uniform partitioning. The performance gain is shown to be universal over a variety of channels, from canonical channels such as additive white Gaussian noise and binary symmetric channels, to practical channels underlying flash memory and magnetic recording systems.

Torque ripple of permanent magnet synchronous motor (PMSM) and load disturbances are the main influencing factors that restrict the application of PMSM in low-speed tracking systems. To improve the speed tracking precision of the gimbal servo system in control moment gyro (CMG) with multisource disturbances, this article proposes a composite control method based on parameter-optimized extended state observers (ESOs) with sliding mode control in the speed loop and PI control with a feed-forward compensation in the current loop. Three ESOs are employed to estimate the disturbances on the $d$ -axis current, the $q$ -axis current, and the load torque so that the controller can have the corresponding parts to compensate for the disturbances. In particular, aiming at the contradiction between the estimation quality of the observer and the sensitivity to the measurement noise, an appropriate cost function is designed to take a compromise between the lumped disturbances and measurement noise and optimize the parameters of the ESOs. Finally, simulation and experimental results on the gimbal servo system of magnetically suspended control moment gyroscope (MSCMG) show the effectiveness of the proposed methods.

Controlling nitrogen oxides (NOx) emissions is increasingly important because of its multiple harmful effects on health and the environment. Carbon monoxide selective catalytic reduction (CO-SCR), a simple and low-cost technology for reducing NOxthrough CO, is considered as a promising method for reducing NOxand CO emissions from the industrial flue gases. As an environmentally friendly catalyst, manganese-based catalysts, which exhibit excellent NO conversion rate, have been extensively studied in NO reduction by CO. In this paper, the catalytic performance of Mn-based catalysts in CO-SCR and its influencing factors were reviewed, and the possible reaction mechanisms were discussed. In addition, different modification methods were used to improve the catalytic performance and anti-poisoning ability of Mn-based catalysts, so that the catalysts could maintain good catalytic performance in the presence of complex components such as oxygen, heavy metals, water vapor, and sulfur dioxide in the exhaust gas. Finally, further research on Mn-based CO-SCR catalysts was prospected.

This study focuses on the generation of the bubble-free layer during the fabrication of the metal foam using the direct melt foaming method. The theoretical models for the three stages during the foaming process have been established, and the boundary conditions have been discussed. The results from the theoretical study indicated that the bubble number of the liquid foam played a critical role in the generation of the bubble-free layer, thus, improving the bubble number retards the velocity of the bubble-free layer generation. The liquid film rupture led to the expansion of the local cross-sectional area of the Plateau border channel and increased the drainage velocity, thus, resulting in an enhancement in the bubble-free layer. Additionally, the verification experiments were conducted by employing the graphene nanoflakes (GNFs) as the heterogeneous nucleation agent. The findings indicated that the generation of the bubble-free layer was hindered, and the bubble-free layer was altogether absent in case the content of the heterogeneous nucleation agent was enhanced.

Insufficient antigen self-presentation of tumor cells and ineffective antigen cross-presentation by dendritic cells (DCs) contribute to diminished immune recognition and activation, which cause resistance to immunotherapies. Herein, we present an ultrasound-activatable in situvaccine by utilizing a hybrid nanovesicle composed of a thylakoid (TK)/platelet (PLT) membrane and a liposome encapsulating DNA methyltransferase inhibitor zebularine (Zeb) and sonosensitizer hematoporphyrin monomethyl ether (HMME). Upon local exposure to ultrasound, reactive oxygen species (ROS) are generated and induce the sequential release of the payloads. Zeb can efficiently inhibit tumor DNA hypermethylation, promoting major histocompatibility complex class I (MHC-I) molecules-mediated antigen self-presentation to improve immune recognition. Meanwhile, the catalase on the TK membrane can decompose the tumoral overexpressed H2O2into O2, which boosts the generation of ROS and the destruction of tumor cells, resulting in the in situantigen release and cross-presentation of tumor antigens by DCs. This in situvaccine simultaneously promotes antigen self-presentation and cross-presentation, resulting in heightened antitumor immunity to overcome resistance.

Backgrounds: Tinnitus is a meaningless sound signal perceived by the patients in the absence of auditory stimuli. Due to the complex etiology and unclear mechanism, specific therapies for tinnitus are still in the exploratory stage. In recent years, personalized and customized music therapy has been proposed as an effective method for tinnitus treatment. The aim of this study was to explore the efficacy of customized therapy with a well-designed follow-up system in the treatment of tinnitus through a large sample one arm study and to identify the relevant factors affecting the treatment outcome. Methods: The study investigated a total of 615 patients with unilateral or bilateral chronic tinnitus who received personalized and customized music therapy for 3 months. A complete follow-up system was designed by the professionals. Questionnaires of Tinnitus Handicap Inventory (THI), Hospital Anxiety and Depression Scale (HADS) and Visual Analogue Scale (VAS) were used to evaluate the therapeutic effects and relevant factors affecting the efficacy of therapy. Results: The results showed a decreasing trend in THI and VAS scores after 3 months of therapy, with statistically significant differences between pre- and post-therapy time points (P< 0.001). All patients were divided into 5 groups according to THI scores, and the mean reduction score in catastrophic, severe, moderate, mild and slight group was 28, 19, 11, 5, 0 respectively. The proportion of tinnitus patients with anxiety was higher than that with depression (70.57% and 40.65%, respectively), and there were statistically significant differences between HADS-A/D scores pre- and post-therapy. Binary logistic regression showed that the baseline of THI, VAS scores, the duration of tinnitus and the state of anxiety prior to therapy were significant influencing factors of therapeutic efficacy. Conclusions: The magnitude of reduction in THI scores after music therapy depended on the severity of the patients' tinnitus, the higher the initial THI scores, the greater the potential for improvement in tinnitus disorders. Music therapy also reduced the anxiety and depression levels of tinnitus patients. Therefore, personalized and customized music therapy with a comprehensive follow-up system may be an effective treatment option for chronic tinnitus patients. Graphical abstract:

ABSTRACTImpact limiters installed on nuclear spent fuel transport casks are used to absorb energy and limit overload during transport and accidents. The two-way corrugated aluminum honeycomb, a new kind of filler material, is designed based on the action mechanism of the impact limiter. Quasi-static compression tests are used to compare the properties of the honeycomb and the traditional filler material, paulownia wood. Experimental results indicated that the compressive and energy absorption properties of paulownia wood with axial wood grain and radial wood grain were very different. Also, the moisture content of paulownia wood led to a significant decrease in its properties. The two-way corrugated aluminum honeycomb, as a new porous material, showed better compression and energy absorption properties than paulownia wood in the x, y, and z directions. The peak stress (σpe), platform stress (σpl), and energy absorption capacity (WEA) were 2.10 times, 2.07 times, and 1.69 times higher than that of paulownia wood with axial wood grain. The two-way corrugated aluminum honeycomb is a filler material that has essential application value in impact limiters of spent fuel transport casks.

In this paper, an ultrasensitive electrochemical biosensor based on carboxylated multi-walled carbon nanotube/molybdenum disulfide composites (MWCNTs-COOH/MoS2) for the detection of KRAS gene is described. An easy, low-cost method, named one-step hydrothermal, was used for the synthesize of MWCNTs-COOH/MoS2nanocomposites, and scanning electronic microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used for characterizing the prepared composites. Furthermore, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed for an electrochemical performance study of this biosensor. Under optimal conditions, the detection limit of target DNA achieved down to 3 fM (S/N= 3) with high sensitivity; the linear range with the logarithm of the concentrations of target DNA varied from 1.0 × 10−14to 1.0 × 10−7M. Finally, the practicality of our proposed sensor was verified by a determination of the KRAS gene in human serum samples with good accuracy and high precision due to the excellent conductivity and large active surface area of the MWCNTs-COOH/MoS2nanocomposites. This proposed biosensor thus provides a practical method for the rapid and sensitive analysis of gene detection.

Monitoring the pH in living cells is of great significance for a deeper understanding of cellular functions for effective disease diagnosis. Herein, a rare example of N-doped carbon dots (N-CDs) that emit bright-yellow fluorescence prepared using o-phenylenediamine as a carbon precursor viaa simple one-pot hydrothermal method is reported. The as-prepared N-CDs exhibited not only highly optical stability and good biocompatibility but also pH sensitivity. A good linear relationship between the fluorescence intensity and the pH value could be obtained in the range of 4.2 to 7.0 (R2= 0.9983). In addition, N-CDs also possess superior selectivity toward hydrogen ions over common metal ions and some bioactive molecules. On this basis, N-CDs are successfully applied to cellular imaging and to monitor pH fluctuations in living cells.

Three dihydroxybenzene isomers, hydroquinone (HQ), catechol (CC) and resorcinol (RS), were determined simultaneously by an ultrasensitive electrochemical sensor based on a glassy carbon electrode modified by multiwalled carbon nanotube@reduced graphene oxide nanoribbon (MWCNT@rGONR) composite. The material was synthesized via hydrothermal method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). We used cyclic voltammetry (CV) to study the electrochemical performance of the three isomers and differential pulse voltammetry (DPV) to optimize the experimental parameters. Based on the optimal experimental condition, our electrochemical sensor displayed a good linear relationship with the concentration range of 15 to 921 uM, 15 to 1101 uM, and 15 to 1301 uM and detection limit of 3.89 uM, 1.73 uM and 5.77 uM for HQ, CC and RS respectively. The electrochemical sensor based on MWCNT@GONR composite showed outstanding ability of reproducibility, stability and anti-interference. In addition, this sensor was also used successfully for simultaneous determination of HQ, CC and RS in real samples with satisfactory result.

Hypoxia leads to endothelial cell inflammation, apoptosis, and damage, which plays an important role in the complications associated with ischemic cardiovascular disease. As an oxidoreductase, p66Shc plays an important role in the regulation of reactive oxygen species (ROS) production and apoptosis. Ketamine is widely used in clinics. This study was designed to assess the potential protective effect of ketamine against hypoxia-induced injury in human umbilical vein endothelial cells (HUVECs). Moreover, we explored the potential mechanism by which ketamine protected against hypoxia-induced endothelial injury.

Three dihydroxybenzene isomers, hydroquinone (HQ), catechol (CC) and resorcinol (RS), were determined simultaneously by an ultrasensitive electrochemical sensor based on a glassy carbon electrode modified by multiwalled carbon nanotube@reduced graphene oxide nanoribbon (MWCNT@rGONR) composite. The material was synthesized via hydrothermal method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). We used cyclic voltammetry (CV) to study the electrochemical performance of the three isomers and differential pulse voltammetry (DPV) to optimize the experimental parameters. Based on the optimal experimental condition, our electrochemical sensor displayed a good linear relationship with the concentration range of 15 to 921 μM, 15 to 1101 μM, and 15 to 1301 μM and detection limit of 3.89 μM, 1.73 μM and 5.77 μM for HQ, CC and RS respectively. The electrochemical sensor based on MWCNT@GONR composite showed outstanding ability of reproducibility, stability and anti-interference. In addition, this sensor was also used successfully for simultaneous determination of HQ, CC and RS in real samples with satisfactory result.